Reliability Test Bank

Which of the following actions is used to prevent voltage collapse when reactive resources are insufficient? Offset scheduled frequency. Implement load reduction. Lower transmission voltage regulator settings. Reduce generator output.

Implement load reduction. NERC Standard VAR-001 states, "Each Transmission Operator shall operate or direct the operation of capacitive and inductive reactive resources within its area; including, reactive generation scheduling; transmission line and reactive resource switching and; if necessary, load shedding - to maintain system and interconnection voltages within established limits." Of the options specified in the standard, "implement load reduction" is the only one listed as one of the choices in this question. - NERC Standard VAR-001

You are a Reliability Coordinator experiencing a flow gate that has become overloaded because a parallel 345 kV line has relayed out causing an SOL violation. What would you do to relieve this violation? Implement the appropriate transmission loading relief procedures Order the line be placed back in service within 30 minutes. Notify the affected Reliability Coordinator and ask them to resolve this issue Issue a warning to the Transmission Operators that lost the 345 kV line.

Implement the appropriate transmission loading relief procedures. Megawatts flow on the path of lowest impedance. When the 345 kV line relayed out, the path of lowest impedance is the flow gate that has now become in violation of an SOL and/or IROL. The Reliability Coordinator has the authority to relieve any transmission facility that is an actual or potential reliability concern. One of the options available is to use is transmission loading relief procedures which curtails interchange that contribute to the line overload.

What is the role of the Sink Balancing Authority when directed by the Reliability Coordinator to modify a Confirmed Interchange or Implemented Interchange for reliability-related reasons? Implement the change then submit a Reliability Adjustment Arranged Interchange within 60 minutes. Submit a Request for Interchange Adjustment and once all approvals are received, implement the change Submit a Reliability Adjustment Arranged Interchange within 30 minutes, then implement the change Contact all Balancing Authorities on the path to ensure the change can be implemented

Implement the change then submit a Reliability Adjustment Arranged Interchange within 60 minutes. R2 - Each Sink Balancing Authority shall ensure that a Reliability Adjustment Arranged Interchange reflecting a modification is submitted within 60 minutes of the start of the modification if a Reliability Coordinator directs the modification of a Confirmed Interchange or Implemented Interchange for actual or anticipated reliability-related reasons.

Each Transmission Operator is required to have a system restoration plan. What is the first thing a Transmission Operator must do when energizing a blacked out area? Turn all voltage regulators to the manual position. Close any capacitor banks which are open. Isolate the load. Contact the Regional Reliability Organization.

Isolate the load. EOP-005, System Restoration - Each Transmission Operator shall have a restoration plan approved by its Reliability Coordinator. The restoration plan shall allow for restoring the Transmission Operator's System following a Disturbance in which one or more areas of the Bulk Electric System (BES) shuts down... Prior to energizing an area that has been blacked out, the load must be isolated so that restoration can proceed in a controlled manner where load is restored in increments to stabilize frequency and voltage as the restoration proceeds.

A Balancing Area's ACE is -40 MW at 1525 hours when the Balancing Authority loses 800 MW of generation. Initial governor action arrests frequency decay and shows the BA's ACE is now -852 MW. At 1542 hours, the BA's ACE is -42 MW and the system frequency is 60.001 Hz. Assuming this event meets the Disturbance Control Standard (DCS) reporting criteria, what other actions is the BA required to take? The BA must over generate for the hour to minimize inadvertent The BA must notify the RC that Energy Emergency Alert is required to return ACE to ZERO. No further system operating action is required. The BA recovered more than 80% of its most severe single largest contingency within 15 minutes.

No further system operating action is required. The Contingency Event Recovery period for loss of generation during a reportable event is 15 minutes. The requirement is to return ACE to its pre-disturbance value within 15 minutes. The BA loses 800 MW and it is a reportable event but does not return ACE to its pre-disturbance value within 15 minutes the BA violates the Disturbance Control Standard. Once the BA is helping the system frequency and providing CPS1 support. No further system operating action is required. NERC Standard BAL-002

Transmission Operator recognizes that potential or actual line loadings, and voltage or reactive levels are such that a single Contingency could threaten the reliability of the Interconnection. What action is required of the Transmission Operator? Notify the Reliability Coordinator via telephone and ask the Reliability Coordinator to pass the word on to others. Notify other Transmission Operators via individual telephone calls. Notify all Transmission Operators and Balancing Authorities via an Interconnection-wide telecommunications system. Notify its Reliability Coordinator, and all other potentially affected Balancing Authorities and Transmission Operators

Notify its Reliability Coordinator, and all other potentially affected Balancing Authorities and Transmission Operators. Application of Transmission Operation Standard TOP-001: Each Transmission Operator shall inform its Reliability Coordinator, known impacted Balancing Authorities, and known impacted Transmission Operators of its actual or expected operations that result in, or could result in, an Emergency.

A Reliability Adjustment Arranged Interchange has been submitted and the Source Balancing Authority for the Interchange must deny it due to a reliability issue. What action must the Balancing Authority take? Inform the Transmission Service Providers of the Denial. Submit a Request for Denial within 10 minutes A Source BA cannot deny a Reliability Adjustment Arranged Interchange Notify the BA's Reliability Coordinator of the denial within 10 minutes

Notify the BA's Reliability Coordinator of the denial within 10 minutes. NERC Standard INT-006 R3.1 - If a Balancing Authority denies a Reliability Adjustment Arranged Interchange, the Balancing Authority must communicate that fact to its Reliability Coordinator no more than 10 minutes after the denial.

After a major disturbance, Interconnection frequency is remaining around 59.92Hz, your Balancing Authority's ACE is 0 and you have 200 MW of extra generation. What should the Balancing Authority system operator do? Offer assistance to entities needing it Shed Load Change the AGC mode to Flat Frequency Increase Generation

Offer assistance to entities needing it. After a disturbance where frequency declines significantly, the entire Interconnection will react (automatically) with governors increasing generation and load decreasing slightly. Load and Generation will rebalance at a lower frequency until generation is increased to return the Interconnection frequency to 60.00 Hz. The best answer is to offer assistance to the deficient Balancing Authority by offering the 200 MW of reserves in a bilateral interchange transaction to help restore generation and load balance in the Interconnection.

Which of the following actions is appropriate for preserving the reliability of the Interconnection during a low voltage emergency? Arrange for interchange sales during high price periods Raise generator voltages Switch in reactors Removing key transmission lines from service

Raise generator voltages. Generators can produce dynamic reactive resources which are critical in controlling voltages. When voltages are low raising generator voltages in unison will increase system voltages.

A Transmission line is loaded at 125% of its System Operating Limit. A parallel line is out for structure maintenance and will take several hours to return to service. Which of the following actions would be acceptable in these conditions? Open the overloaded line immediately. Decrease the voltage setpoints on the generators in the area Wait until the parallel line is restored. A 25% overload is acceptable if the parallel line is returned by the end of the day. Re-dispatch generation to decrease loading on the line.

Re-dispatch generation to decrease loading on the line. Re-dispatching generation would be first action to take if available to try to unload the line.

Balancing Authorities must provide information regarding operating reserves to their Reliability Coordinators. What type of information must be provided? Regulating and Contingency Reserves Spinning and synchronized reserve only Forecast Peak Generator Output commitments

Regulating and Contingency Reserves. Operating Reserves are that capability above firm system demand required to provide for regulation, load forecasting error, equipment forced and scheduled outages and local area protection. It consists of spinning and non-spinning reserve. NERC Standard TOP-003, titled Operational Reliability Data requires the Balancing Authority to maintain a documented specification for the data necessary for it to perform its analysis function and Real-time monitoring.

Entities that have a reliability relationship with a Reliability Coordinator are required to provide the data it needs to monitor and assess the operations of its _______________________. entire Transmission and Distribution system Bulk Electric System Reliability Coordinator Area Area Control Error

Reliability Coordinator Area. NERC Standard IRO-010: Reliability Coordinator Data Specification and Collection is to prevent instability, uncontrolled separation, or Cascading outages that adversely impact reliability, by ensuring the Reliability Coordinator has the data it needs to monitor and assess the operation of its Reliability Coordinator Area.

You are a Reliability Coordinator in area Z. You have issued a Transmission Loading Relief procedure to relieve a constrained flowgate on the contract path that includes the Reliability Coordinator in area M where the Sink Balancing Authority is located. You have notified all other Reliability Coordinators via the Reliability Coordinator Information System. The Sink Balancing Authority for the curtailed Interchange Transaction should be notified by whom? The Transmission Provider for the Sink Balancing Authority Reliability Coordinator for area M The Power Marketer that set up the Interchange Transaction Reliability Coordinator for area Z

Reliability Coordinator for area M. Typically, the Reliability Coordinator initiating the TLR notifies all other Reliability Coordinators via the RCIS system. Each Reliability Coordinator and Balancing Authority that receives a request pursuant to an Interconnection-wide transmission loading relief procedure (such as Eastern Interconnection TLR, WECC Unscheduled Flow Mitigation, or congestion management procedures from the ERCOT Protocols) from any Reliability Coordinator, Balancing Authority, or Transmission Operator in another Interconnection to curtail an Interchange Transaction that crosses an Interconnection boundary shall comply with the request, unless it provides a reliability reason to the requestor why it cannot comply with the request. - NERC Standard IRO-006

During a system restoration, what is the system operators priority? Interconnection frequency Restoration of interchange Restoration of off-site startup power to generating facilities Restoration of customer load

Restoration of off-site startup power to generating facilities. EPRI - Power System Restoration 11-62 It is critical to ensure the off-site power to generating facilities to avoid damage to the generator.

The Interconnections is not experience any disturbances or overloads. A Balancing Authority notifies the Reliability Coordinator that the projected load in a Balancing Area for the next three hours (over the morning peak) is trending above the available generation that had been committed for the day. Operating Reserves will be required to be converted into energy to cover the shortfall. What is the most likely cause of the shortfall? The largest capacity generator in the Balancing Area tripped off line. The Load Forecast for the day was greatly underestimated. There was a curtailment of the largest import on the Interchange Schedule. A generator operator failed to notify the Balancing Authority that one of their generators was de-rated by 30% of its capacity.

The Load Forecast for the day was greatly underestimated. Operating reserves are that capability above firm system demand required to provide for regulation, load forecasting error, equipment forced and scheduled outages and local area protection. It consists of spinning and non-spinning reserve. If an hourly load forecast greatly underestimate the load, a shortfall of available generation to cover load and reserves is likely due to not committing enough generation for the day. The instantaneous loss of generation, cutting Interchange Scheduled purchases and de-rating generators are covered within the reserve requirement. If reserves are needed to cover load, then the BA is not meeting load and reserves requirements.

If a line is loaded above its SIL, how does that affect the line and the voltage? The line becomes less inductive and the voltage increases. The line becomes more inductive and the voltage increases. The line becomes more inductive and the voltage drops. The line becomes less inductive and the voltage in constant.

The line becomes more inductive and the voltage drops. The Surge Impedance Loading, or SIL, is the MW loading on a transmission line at which the line's natural reactive power production equals its reactive power usage. If the MW loading exceeds the SIL, the transmission line will consume more MVAR than it is producing causing voltage to decline. EPRI Figure 5-8

The largest single contingency for Balancing Authority A is a unit rated at 900 MW. Which of the following disturbances would constitute a reportable disturbance for DCS evaluation based on the NERC DCS criteria? The loss of two 400 MW units 30 seconds apart. The loss of 750 MW of firm load. The loss of the 900 MW generating unit at 60% output. The loss of a 700 MW generating unit at 100% output.

The loss of two 400 MW units 30 seconds apart. BAL-002, Reportable Balancing Contingency Event (NERC Glossary) is Any Balancing Contingency Event occurring within a one-minute interval of an initial sudden decline in ACE based on EMS scan rate data that results in a loss of MW output less than or equal to the Most Severe Single Contingency, and greater than or equal to the lesser amount of: (i) 80% of the Most Severe Single Contingency, or (ii) the amount listed for the applicable Interconnection. Eastern Interconnection - 900 MW, Western Interconnection - 500 MW, ERCOT - 800 MW, Quebec - 500 MW

Which of the following would you expect to experience during a Geo-Magnetic disturbance? Significant low frequency induced currents enter the system through the grounded transformer neutrals, causing system overloads and harmful system wide harmonics. Significant high frequency induced currents enter the system through the grounded transformer neutrals, causing system overloads and harmful system wide harmonics. System frequency declines below an acceptable operating level, and generator governors are required to take action to arrest the frequency decline. System voltages increase beyond safe operating levels. Requiring the operator to take action to absorb VARs from the system or decrease voltage schedules.

Significant low frequency induced currents enter the system through the grounded transformer neutrals, causing system overloads and harmful system wide harmonics. EPRI 2009 Power System Dynamics Tutorial, Chapter 9 & 11: The major harm from GMDs results from low frequency GICs (geomagnetic induced currents) entering the power system via the transformer grounded neutrals. These currents can be so large that the transformers are damaged and severe harmonics are produced.

Re-synchronization with the Interconnection should only be attempted at a _____________. Generating plant with an auto-synchronization relay Substation with auto re-closing relays Substation with a synchroscope Substation with an auto-synchronization relay

Substation with a synchroscope. EPRI 11.6.4 When a restoration plan is first developed, the plan's developers must determine where synchronizing equipment is located within the power system and whether the equipment is at the correct locations. The most likely place for restoration is at a substation equipped with the sync scope.

Which indicators alert operator to potential emergency conditions? Sudden increase in call volume Sudden changes in system frequency and voltage Sudden increase in system load Sudden changes in Interchange transactions

Sudden changes in system frequency and voltage.

Interconnection frequency is 59.80 Hz. Your ACE is a large negative value and your AGC is pulsing your units down. What should you do? Place AGC in constant frequency control. Leave AGC in operation but investigate. Place AGC in flat tie line control. Suspend AGC and investigate.

Suspend AGC and investigate. In this scenario, the AGC clearly is not operating correctly (pulsing units down when ACE is negative) and given that the frequency has dramatically declined to 59.80 Hz that has an adverse impact to the reliability of the Interconnection. Therefore, suspending AGC and going to manual control to adjust generation is the recommended course of action.

What is the most common cause of frequency fluctuations? System generation and load imbalance Market activity Power losses Load shed

System generation and load imbalance Frequency of the Interconnection is determined by the total Interconnection load and total Interconnection generation. Any mismatch of load and generation will result in the Interconnection frequency deviating from the scheduled frequency.

Reliability Coordinator's communicate and coordinate changes in system conditions to its member organizations and directs specific steps so that Interconnection remains in current condition Operators can complete their shift System reliability is not adversely impacted Actual conditions match forecasted conditions

System reliability is not adversely impacted. The RC is in constant contact with the organizations under their direction keeping them abreast of any system conditions that could impact the reliability of the Interconnection.

An 80 mile transmission line from Substation A to Substation B trips. The field crew reports a Zone 2 target at Substation A and a Zone 1 target at Substation B. Where is the fault anticipated to be? Outside of the line segment Within 8 miles of Station B Midway between A and B Within 8 miles of Station A

Within 8 miles of Station B. Distance relays application: A Zone 1 relay will typically monitor 90% of a line while a Zone 2 relay will typically monitor 120% of the line. In this problem, a Zone 2 was reported at Station A indicating the fault is up to 120% away from Station A looking toward Station B. A Zone 1 was reported at Station B indicates the fault is within 90% of Station B. Since Station A did not trip on Zone 1 then the fault is past 90% range and closer to Station B and likely within 10% range of Station B. Therefore, the fault is anticipated to be within 8 miles of Substation B.

Insulator maintenance must be performed on a 230 kV line. Maintenance personnel inform you that the line must be de-energized tomorrow to perform the maintenance. In the past, outages of this line on high load days have resulted in SOL violations on your system. This outage must be coordinated with? Only Transmission Operators or Balancing Authorities that participate in the outage. Only Transmission Operators or Balancing Authorities that are adjacent to your system. Your Reliability Coordinator and any Transmission Operator or Balancing Authority that may be impacted by the outage. Only Reliability Coordinators, Transmission Operators, and Balancing Authorities that request information about the outage.

Your Reliability Coordinator and any Transmission Operator or Balancing Authority that may be impacted by the outage. NERC Standard TOP-001: Each Transmission Operator shall inform its Reliability Coordinator, known impacted Balancing Authorities, and known impacted Transmission Operators of its actual or expected operations that result in, or could result in, an Emergency.

A Reliability Coordinator shall know the current status of ________________ whose failure, degradation or disconnection could result in an SOL or IROL violation. all generator Mvars all transformers tap positions all operating reserves available all critical facilities

all critical facilities. NERC Standard IRO-002: Each Reliability Coordinator shall monitor Facilities, the status of Remedial Action Schemes, and non-BES facilities identified as necessary by the Reliability Coordinator, within its Reliability Coordinator Area and neighboring Reliability Coordinator Areas to identify any System Operating Limit exceedances and to determine any Interconnection Reliability Operating Limit exceedances within its Reliability Coordinator Area.

Operational Planning Analysis is a Reliability Analysis studies conducted by Reliability Coordinators for the purpose to assess whether the planned operations for the next day within its Wide Area, will exceed Operating limitations of generating facilities Available Transfer Capability Cost/profitability of maintaining economic dispatch any of its Interconnection Reliability Operating Limits

any of its Interconnection Reliability Operating Limits. NERC Standard IROL-008: Each Reliability Coordinator shall perform an Operational Planning Analysis that will allow it to assess whether the planned operations for the next-day will exceed System Operating Limits (SOLs) and Interconnection Operating Reliability Limits (IROLs) within its Wide Area.

The loading on a transmission line is to the point at which the MVAR supplied from the lines natural capacitance equals the MVAR the line needs to support its voltage. This is known as ___________________. instantaneous peak surge impedance loading maximum loading point (MLP) integrated peak

surge impedance loading Transmission Operations Application: Surge Impedance Loading, or SIL, is an important concept for controlling voltage levels. The question states that the loading on a transmission line is to the point at which the MVAR supplied from the lines natural capacitance equals the MVAR the line needs to support its voltage. This is known as Surge Impedance Loading, the point where the MW transfer on the line requires 0 Mvar from the system to support voltage. EPRI Chapter 5

If a real-time control center becomes non-operational for whatever reason, the real-time system operators are expected to _________________. continue to meet its functional obligations regarding the reliable operations of the BES notify its Regional Reliability Organization read the Operating Plan for backup functionality for the first time change to automatic control and evacuate

continue to meet its functional obligations regarding the reliable operations of the BES. Each Reliability Coordinator, Balancing Authority, and Transmission Operator shall have a current Operating Plan describing the way in which it continues to meet its functional obligations regarding the reliable operations of the BES in the event its primary control center functionality is lost. - NERC Standard EOP-008

Strategically placing generators on line in a Balancing Area to alter or change the flow of active and reactive power on a transmission system is ____________________. dispatching for Reliability or Reliability Dispatch Power reallocation Generation Lambda Economic Dispatch

dispatching for Reliability or Reliability Dispatch. Reliability dispatch is to bring on generator to ensure system reliability, it can alter the flow of active and reactive power and is used to unload transmission lines by generating megawatts and reactive power in an area to reduce line loading. - NERC Standard VAR-001

Generators, synchronous condensers, and Static VAR Compensator are examples of which type of reactive resources? dynamic rotating stationary static

dynamic. NERC Standard VAR-001 Purpose is to ensure that voltage levels, reactive flows, and reactive resources are monitored, controlled, and maintained within limits in Real-time to protect equipment and the reliable operation of the Interconnection. Transmission Operators shall have sufficient resources to regulate voltage levels under normal and Contingency conditions. Dynamic reactive resources include generators, synchronous condensers, static VAR compensator and lightly loaded transmission lines because they can provide reactive support as needed without operator actions. A shunt capacitor is considered a static reactive resource.

In the event a Balancing Area experiences multiple contingencies occurring within _________ of each other, it shall be treated as a single contingency. five minutes one minute or less two minutes fifteen minutes

one minute or less. Simultaneous Contingencies - Multiple Contingencies occurring within one minute or less of each other shall be treated as a single Contingency. If the combined magnitude of the multiple Contingencies exceeds the most severe single Contingency, the loss shall be reported, but excluded from compliance evaluation. NERC Standard BAL-002, Section D. 1.5 Simultaneous Contingencies

In your Interconnection, a generator tripped that was large enough to reduce the frequency from 60.00 Hz to 59.94 Hz. Your Balancing Authority's Frequency Bias is -200 MW/0.1 Hz. How many MW would your system initially contribute to frequency support? 200 MW 120 MW 100 MW 80 MW

120 MW. BAL-003, Each Balancing Authority shall achieve an annual Frequency Response Measure (FRM) (Attachment A) that is equal to or more negative than its Frequency Response Obligation (FRO) to ensure that sufficient Frequency Response is provided by each BA or Frequency Response Sharing Group (FRSG). For Example: Frequency Bias (which is always a negative number) is measured in MW per tenth Hz (MW/0.1Hz) means if scheduled frequency is 60.00 Hz and actual frequency drops to 59.90 Hz, a Balancing Authority with a 200 MW/0.1 Hz Frequency Bias would contribute 200 MW to help arrest the frequency decline. The frequency portion of the ACE equation is -[10*B*(Fa - Fs)]. If Frequency drops to 59.94 Hz then - (10 * -200 MW/0.1 Hz) * (59.94 Hz - 60.00 Hz) = -(- 2000 MW/Hz * -0.060 Hz) = -120 MW. To return ACE to zero, your Balancing Authority would have to over generate by 120 MW. This should happen with the response of your generator governors and loads due to the declining frequency.

The total capacity of a facility in a transmission path is 1600 MW. The Available Transfer Capability of the same path from A to B is 1200 MW. An unscheduled (parallel) flow of 600 MW is also present from A to B. What is the maximum net interchange that can be scheduled from A to B? 1600 MW 1200 MW 1000 MW 600 MW

1200 MW. Available Transfer Capability (ATC) is calculated using forecasted loads, facility status, generation online, transmission outages, and scheduled interchange. Parallel flow is considered as the power flows are increased until a limit is reached, and the transfer capability is set.

With regards to Voltage Control Theory, as long as power angles are less than ______ degrees, reactive power will flow from the higher to the lower voltage magnitude. 180 10 20 90

20. The power angle is the Voltage phase angle difference between two locations in the power system. The reactive power transferred between two points is determined by the voltage magnitudes at the two points and the cosine of the power angle between the points. Reactive power does normally flow from the high to the low voltage bus. This is a rule of thumb every system operator should know. However, ... we assumed the power angle was small and so ignored the cosine term. If δ had been large (> 20°), we could not have ignored the cosine term. When power angles exceed approximately 20°, the rule of thumb that reactive power flows from high to low voltage no longer applies. EPRI 3.3.3

What type of relays would you most likely find on each end of a 75 mile 230KV transmission line? 21 Distance and a 64 Ground or 67 Directional Overcurrent 49 Thermals 27 Voltage or 25 Synchronous check 87 Differentials

21 Distance and a 64 Ground or 67 Directional Overcurrent. Transmission lines are usually protected by distance relays and ground overcurrent relays. Whether the relays are electromechanical, solid state, or computer type relays does not matter when it comes to the numbering for the distance relays. That number will usually be a 21 set by IEEE. The ground relay may have a different number. For example, if the ground relay is an older electromechanical directional ground relay, there might be a 64. If the relay is the newer computerized relay, there will be a 67, which represents a directional overcurrent type relay. Whatever the case, lines are usually protected by 21 distance and 64 or 67 directional ground or directional overcurrent relays. - NERC Standard PRC-001 Requirements R1, Page 1 of 2

A 400 MW Interchange Transaction from 1300 to 1400 is in progress. At 1345 the schedule is curtailed to 0 MW. What was the MW profile for the hour? 0 MWh 400 MWh 200 MWh 300 MWh

300 MWh. IF the 400 MW schedule had flowed the entire hour then it would have been 400 MW for the entire hour or 400 MWh. Since it flowed for 3/4 of the hour you can calculate 3/4 of 400 MWs. In reality you have an instantaneous flow of 400 MW for 45 minutes and then 0 MW instantaneous flow for 15 minutes. To calculate the MW for the entire hour (MWh) you average the amounts.

A transformer rated at 50 MVA is currently carrying 30 MW of load. At this load, what is the maximum allowable MVAR flow through the transformer? 40 MVAR 30 MVAR 50 MVAR 0 MVAR

40 MVAR. Using the power triangle, this is a 3-4-5 case, or 30-40-50. Therefore 40 MVAR is the limit with the 30 MW flow.

A firm transaction is set to start at the top of the hour that will overload a constraint to 10 MW above an identified SOL. Non-firm transactions are running that have PTDFs of 0.2 on the constrained path. How much non-firm Interchange will have to be cut in order to stay within the SOL? 10 MW 20 MW 100 MW 50 MW

50 MW. The Power Transfer Distribution Factor is 0.2. The amount of relief needed on the line is 10 MW. In order to get 10 MW of relief you must curtail 50 MW of an Interchange with a PTDF of .2. 10 MW / 0.2 = 50 MW

When a system is in an island, how much load needs to be shed to compensate for a 1 Hz deviation in frequency? 3 to 5 % 10 to 12 % 6 to 10 % 1 to 2 %

6 to 10 %. EOP-011 requires Balancing Authorities and Transmission Operators to develop Operating Plans, that include load shed. The NERC Electric System Restoration Reference Document states, "In an islanded area, generation and load should be adjusted in small increments to minimize the impact on frequency. As a rule, shed six to ten percent (6-10%) of load to restore the frequency approximately 1 Hz."

Transient instability occurs when a disturbance on the system causes power angles to exceed_________ . 120 degrees 90 degrees 180 degrees 10 degrees

90 degrees. Transient instability occurs when a disturbance such as a fault on the system causes power angle excursions greater than 90 degrees that makes the system unstable. System stability is a consideration in developing System Operating Limits (SOLs). NERC Standard TOP-001: Each Transmission Operator shall not operate outside any identified IROL limits and shall initiate its Operating Plan to mitigate an SOL exceedance. Operating to the most limiting parameter in instances where there is a difference in the SOL.

Balancing Authority ABC is a member of a Reserve Sharing Group (RSG). At 0605 Balancing Authority ABC loses a 500 megawatt generator. At 0610 it calls on its RSG to replace the lost generation until Balancing Authority ABC can get more generation, such as gas turbines on line and loaded. What time must Balancing Authority ABC stop using RSG power to avoid having to submit a Request for Interchange? 0650 0710 0705 0750

0705. NERC Reliability Standard INT-010 R1 - The Balancing Authority that experiences a loss of resources covered by an energy sharing agreement or other reliability needs covered by an energy sharing agreement shall ensure that a Request for Interchange (RFI) is submitted with a start time no more than 60 minutes beyond the resource loss. If the use of the energy sharing agreement does not exceed 60 minutes from the time of the resource loss, no RFI is required.

A Balancing Authority has a sudden loss of a large block of load in its area. This loss will be seen instantaneously in the change of which of the following values? 1. Actual Net Interchange 2. Scheduled Frequency 3. Scheduled Net Interchange 4. Area Control Error 1 & 4 3 & 4 1 & 3 4 only

1 & 4. Due to the loss of load in the area, the BA will have excess generation and the excess will be exported into the Interconnection through the tie lines. This will cause the NIa to increase. Scheduled Frequency and Interchange only change when changed by an operator.

The Transmission Operator should consider which of the following when reactive resources are limited? 1. Re-dispatch even if that means going outside of economic dispatch 2. Unload heavily loaded lines through reconfiguration 3. Request reactive power support from lightly loaded systems 4. Direct neighboring area to shed load also 3 and 4 1 and 2 1 and 4 2 and 3

1 and 2. NERC Standard VAR-001: Each Transmission Operator shall operate or direct the Real-time operation of devices to regulate transmission voltage and reactive flow as necessary. System Operators must be aware of the actions that will impact power flow and utilize those options. Re-dispatching generation will shift the power flowing on the transmission system. The amounts will differ depending on Generation Shift Factors of each generator on the specified transmission lines. Re-configuration changes equipment status which will also change the amount of the power flowing on certain paths. For example, returning a line to service will reduce the power flow of a parallel line.

A Transmission Operator must monitor critical reliability parameters in real-time such as; 1) Transmission line status 2) Available resources for use 3) Real and Reactive power flows 4) Weather forecast 1 and 3 3 and 4 2 and 3 1 and 2

1 and 3. NERC Standard TOP-001 application of the requirement that each Transmission Operator shall have the necessary data to perform Real-time Assessments and Real-time Monitoring. Each Transmission Operator shall perform the following as necessary for determining System Operating Limit (SOL) exceedances within its Transmission Operator Area...monitor Facilities and the status of Special Protection Systems, and Outside its Transmission Operator Area, obtain and utilize status, voltages, and flow data for Facilities and the status of Special Protection Systems.

Which of the following is considered to be a reliability event? 1) Low voltage 2) Loss of a small generator 3) SOL or IROL exceeded 4) Loss of Energy Management System 2 and 3 1 and 2 3 and 4 1 and 3

1 and 3. Reliability event is referred to as an event that affects or may potentially affect the reliability of the Bulk Electric System, such as loss of generation, transmission or load or violations or potential violations of operating limits.

Which of the below items does an RC verify prior to approving the synchronization of two islands? 1. Frequency of the Islands are matched 2. Load is balanced for the two areas 3. Load and generation is balanced for the two areas 4. Synchronizing equipment exists at the tie point. 1,3 and 4 1, 2, and 3 1,2 and 4 2,3 and 4

1,3 and 4. EOP-006, System Restoration Coordination: R8: The Reliability Coordinator shall coordinate or authorize re-synchronizing islanded areas that bridge boundaries between Transmission Operators or Reliability Coordinators. If the re-synchronization cannot be completed as expected the Reliability Coordinator shall utilize its restoration plan strategies to facilitate re-synchronization.

A report shall be submitted to NERC following the shedding of at least how much firm load? 200 MW 100 MW 300 MW 50 MW

100 MW. EOP-004 states, Firm load shedding of 100 MW or more to maintain the continuity of the bulk electric system." Firm load shedding of 100 MW or more to maintain the continuity of the bulk electric system also requires a report to DOE. NERC will accept the same report.

NERC requires a report to be submitted following the shedding of at least how much firm load? 200 MW 50 MW 100 MW 300 MW

100 MW. EOP-004, Disturbance Reporting.

Which of the following conditions describes a case where a Balancing Authority is hindering the Interconnection scheduled frequency? ACE is positive while frequency is 60.00 Hz ACE is positive while frequency is below 60.00 Hz ACE is negative while frequency is below 60.00 Hz ACE is negative while frequency is above 60.00 Hz

ACE is negative while frequency is below 60.00 Hz Anytime the ACE of Balancing Authority is the same sign as the frequency error, the BA is considered as hindering the Interconnection and CPS1 scores will be affected negatively.

Which of the conditions must have an Operating Plan developed by the Transmission Operator? Switching transmission elements All the Above Controlling voltage levels Responding to IROL

All the Above. Each Transmission Operator shall initiate its Operating Plan to mitigate an SOL exceedance identified as part of its Real-time monitoring or Real-time Assessment. The Operating Plans are a document that identifies a group of activities that may be used to achieve some goal. Transmission Operators function is more transmission switching, monitoring and controlling voltage, and real and reactive power flow, and responding to SOL/IROL violations.

Which information should be available to the Reliability Coordinators to have adequate analylsis tools to perform their responsibilities? Pre-and post-contingency analysis capabilities (thermal, stability and voltage). State Estimation. Wide-area overview displays. All the above

All the above. NERC Standard IRO-002: Each Reliability Coordinator shall have data exchange capabilities with its Balancing Authorities and Transmission Operators, and with other entities it deems necessary, for it to perform its Operational Planning Analyses.

The Source Balancing Authority must assess the following items of Arranged Interchange before approving: Scheduling path connectivity Megawatt profile including Ramp start and stop times Interchange duration All the answers are correct

All the answers are correct. NERC Standard INT-006 R1. Each Balancing Authority shall approve or deny each on-time Arranged Interchange or emergency Arranged Interchange that it receives and shall do so prior to the expiration of the time period defined in Attachment 1, Column B. 1.1. Each Source and Sink Balancing Authority shall deny the Arranged Interchange or curtail Confirmed Interchange if it does not expect to be capable of supporting the magnitude of the Interchange, including ramping, throughout the duration of the Arranged Interchange. 1.2. Each Balancing Authority shall deny the Arranged Interchange or curtail Confirmed Interchange if the Scheduling Path (proper connectivity of Adjacent Balancing Authorities) between it and its Adjacent Balancing Authorities is invalid.

The coordination of the emergency operating plans the Transmission Operator and Balancing Authority shall include which of the following? Process to prepare for and mitigate Emergencies Cancellation of transmission or generator outages All the answers provided are correct. Roles and responsibilities for activating operating plan

All the answers provided are correct. EOP-011, Emergency Operations - To address the effects of operating Emergencies by ensuring each Transmission Operator and Balancing Authority has developed Operating Plan(s) to mitigate operating Emergencies, and that those plans are coordinated within a Reliability Coordinator Area.

A power system with long transmission lines that connect remote generation to load centers is more likely to have System Operating Limits or Interconnection Operating Limits determined by: Generator thermal limitations Transmission thermal limitations Generator voltage limitation Angle stability limitations

Angle stability limitations. Each Transmission Operator shall operate within the Interconnection Reliability Operating Limits (IROLs) and System Operating Limits (SOLs) to maintain reliability. When generators are connected to load centers using long transmission lines, large power angles are often required to move power to the load center. This results in angle stability limitations being the most likely factor in when evaluating (contingency analysis) the loss of other elements in the Power System.

Governor droop is used to: Restore Frequency to normal Represent energy lost due to inefficiencies in generation Arrest Frequency Variations Maintain Voltage

Arrest Frequency Variations. Governor response is a component of Balancing Authority Frequency Response Characteristic. Generator governor systems determine generator response to frequency deviations based on the droop characteristic of the governor control system. Governor droop controls the generator's response in arresting frequency deviations. A generator's response to frequency deviations will be in proportion to its MW rating allowing many generators on governor control to respond in parallel. EPRI Chapter 4: Frequency Control

You experience a full system shutdown. You are in the process of restoring load and you are concerned about re-collapsing the system. Which is the best approach in the restoration process that will help ensure your system will be restored successfully? If the system has stabilized at below 60 HZ, shed 15% - 20% of the load to raise the frequency to 61 HZ. Avoid energizing loads in excess of 5% of the online generation capacity of the system. Operating reserves should be maintained to cover the largest generator currently in service. Maintain frequency between 59.5 HZ and 60.5 HZ.

Avoid energizing loads in excess of 5% of the online generation capacity of the system. Increasing load too rapidly could result in a re-shutdown of the system. The thumb rule for load restoration is blocks of load not to exceed 5% of the online generation capacity of the system.

Why are high transmission system voltages a problem during system restoration? Because of the excessive MVAR supply from generators. Because of the excessive MVAR supply from energizing transmission lines. Because of shunt reactors that were left in service after the system collapse. Because of insufficient MVAR supply from generators that tripped off.

Because of the excessive MVAR supply from energizing transmission lines. EPRI 2009 Power System Dynamics Tutorial Chapter 11

To conform to the CPS requirement, a Balancing Authority must have a _______. CPS1 greater than or equal to 200%. CPS1 greater than or equal to 100%. CPS1 greater than or equal to 90%. CPS1 less than or equal to 90%.

CPS1 greater than or equal to 100%. To conform to the CPS requirement, a Balancing Authority must have a CPS1 greater than or equal to 100%. NERC Standard BAL-001, Measure M1

The Transmission Operator Area is All equipment in the Balancing Authority area The control room where the Transmission Operator resides. Substation and transmission lines 100 kV or above Collection of Transmission assets that the TO is responsible for operating

Collection of Transmission assets that the TO is responsible for operating.

A Reliability Coordinator notices that transmission voltage at a substation in a neighboring Reliability Coordinator Area has declined to 94% of nominal and is not recovering. Which of the following actions should the Reliability Coordinator take? Start a generator to help with voltage Direct the Reliability Coordinator to increase his voltage Contact the Reliability Coordinator whose area the voltage is declining. Contact the Transmission Operator whose area the voltage is declining.

Contact the Reliability Coordinator whose area the voltage is declining. NERC Standard IRO-02 requires each Reliability Coordinator to have data exchange capabilities with its Balancing Authority and Transmission Operators to perform its Operational Planning Analysis, Real-time Assessments and Real-time monitoring.

An unexpected failure or outage of a system component is referred to as a: Blackout Contingency Deficiency Collapse

Contingency. NERC Glossary: Contingency - The unexpected failure or outage of a system component, such as a generator, transmission line, circuit breaker, switch or other electrical element.

When a Reliability Coordinator is performing the next-day analysis for its Reliability Coordination Area, what information is required for the system study? Interchange transactions, area inadvertent accumulations, staffing summaries, and load. Load, generation, Area Interchange Error (AIE) documents, operations reserve projections, and staffing summaries. Area Interchange Error (AIE) documents, area inadvertent accumulations, weather forecast and geomagnetic forecasts. Critical facility status, load, generation, operation reserve projections, and known interchange transactions.

Critical facility status, load, generation, operation reserve projections, and known interchange transactions. NERC Standard IRO-001: Each Reliability Coordinator shall perform an Operational Planning Analysis that will allow it to assess whether the planned operations for the next-day will exceed System Operating Limits (SOLs) and Interconnection Operating Reliability Limits (IROLs) within its Wide Area. Operational Planning Analysis (OPA) is an evaluation of projected system conditions to assess anticipated (pre-Contingency) and potential (post-Contingency) conditions for next-day operations. The evaluation shall reflect applicable inputs including, but not limited to, load forecasts; generation output levels; Interchange; known Protection System and Special Protection System status or degradation; Transmission outages; generator outages; Facility Ratings; and identified phase angle and equipment limitations. NERC Glossary

A real-time contingency analysis shows that a radial transmission line will overload for the loss of the other line. What is the best course of action for the Reliability Coordinator? Discuss with Transmission Operator and be prepared to direct load shed Skip this real-time contingency result Build more generation at the load Discuss with Transmission Operator and direct load shed in advance of contingency

Discuss with Transmission Operator and be prepared to direct load shed. Application of Transmission Operations - EPRI Power System Dynamics

What type of relay uses a combination of current transformer (CT) measurements and potential transformer (PT) measurements and operates when the ratio of the PT measurement to CT measurement is below a certain limit for a given period of time? Distance relay Time overcurrent relay Lockout relay Differential relay

Distance relay. A distance relay uses a combination of current transformer (CT) measurements and potential transformer measurements (PT) and operates when the ratio of the PT measurements to CT measurements (Voltage/Current, V/I) is below a certain limit for a given period of time. EPRI Chapter 2.5.6. NERC Standard PRC-001 requires that Each Transmission Operator, Balancing Authority, and Generator Operator shall be familiar with the purpose and limitations of Protection System schemes applied in its area.

To be effective, reactive resources should be: Distributed throughout the system. Located close to generation. Centrally located in the system. In areas subject to high voltage.

Distributed throughout the system. VAR-001: Voltage and Reactive Control

Voltage reduction for load relief should be made on the __________. Transmission System Distribution system Tie-lines with other Balancing Authority Areas Entire Interconnection simultaneously

Distribution system. Normally, voltage reduction for load relief should be made on the distribution system. Voltage reduction on the sub transmission or transmission system may be effective in reducing load; however, voltage reduction should not be made on the transmission system unless the system has been isolated from the Interconnection. This is because implementing a voltage reduction on a single system that is still interconnected to its neighbors will have a negative impact on the voltage of neighboring systems as MVAr move from the neighboring systems to the system attempting to reduce its voltage. - NERC Standard TOP-001

A Balancing Authority informs the Reliability Coordinator that the projected load in a Balancing Area for the next four hours (over the morning peak) is trending above the available generation that had been committed for the day. Operating Reserves will be required to be converted into energy to cover the shortfall. Which Energy Emergency Alert (EEA) level should the RC declare? EEA 3 EEA 1 EEA 2 No EEA should be declared until load shed is expected.

EEA 1. EOP-011 Emergency Operations, Attachment 1, Energy Emergency Alerts - Level 1 is when the Balancing Authority is experiencing conditions where all available generation resources are committed to meet firm Load, firm transactions, and reserve commitments, and is concerned about sustaining its required Contingency Reserves.

Balancing Authorities on the Scheduling Path shall be responsible for assessing and approving or denying the Interchange Transaction based on which of the following: 1. Transaction Magnitude 2. Scheduling path 3. OASIS reservation 4. Ramp rate 1, 2 and 3 2, 3 and 4 1, 2 and 4 1, 3 and 4

1, 2 and 4. NERC Standard INT-006 R1 - Each Balancing Authority shall approve or deny each on-time Arranged Interchange or emergency Arranged Interchange that it receives and shall do so prior to the expiration of the time period defined in Attachment 1, Column B. R1.1. Each Source and Sink Balancing Authority shall deny the Arranged Interchange or curtail Confirmed Interchange if it does not expect to be capable of supporting the magnitude of the Interchange, including ramping, throughout the duration of the Arranged Interchange. R1.2. Each Balancing Authority shall deny the Arranged Interchange or curtail Confirmed Interchange if the Scheduling Path (proper connectivity of Adjacent Balancing Authorities) between it and its Adjacent Balancing Authorities is invalid.

Conditions that might require a Reliability Coordinator to notify other Reliability Coordinators include which of the following? 1. Sabotage events 2. Interconnection Reliability Operating Limit violations 3. Voltage reductions 4. Insufficient resources 5. Arming of special protection systems 3, 4, and 5 only 1, 2, and 3 only 1, 3, and 5 only 1, 2, 3, 4 and 5

1, 2, 3, 4 and 5. NERC Standard IRO-014 speaks to the Coordination Among Reliability Coordinators. In additional to Operating Procedures, Operating Processes, and Operating Plans that require notification or coordination of actions that may impact adjacent Reliability Coordinator Areas, the Reliability Coordinator shall notify other impacted Reliability Coordinators upon identification of an expected or actual Emergency in its RC Area.

When synchronizing sections of the transmission system that have separated or islanded, frequency and voltage magnitude on each side of the breaker and the power angle across the breaker must be within proper limits. To bring these values within proper limits, the system operator should _____________________. Adjust the power angle on one side of the breaker to 90 degrees. Open additional lines until the voltage is matched. Adjust generator MW and MVAR output in one of the areas. Adjust the tap changer on the nearest transformer.

Adjust generator MW and MVAR output in one of the areas. EPRI 2.5.7 Power flows from areas of more positive to less positive voltage angles, and reactive power flows from areas of higher voltage to areas of lower voltage. Therefore, to minimize flows across the breaker as it is being closed, these values must be within acceptable ranges on each side of the breaker before closing is attempted. Power flow can be manipulated by adjusting generation on one side of the open breaker. Generation can be raised or lowered to adjust the speed of one section of the system with respect to the other. The power angle is the difference in voltage angles at two points on the system. In this case, when we are discussing the power angle across the breaker we are referencing the difference in voltage angles of the two busses which are connected by a transmission lines that we are trying to synchronize. Most technical references, such at the EPRI Interconnected Power System Dynamics Tutorial, on which the NERC exams are partially based, stress the importance of minimizing power angle across the breaker.

A system operator is anticipating a heavy load day. Which of the following would alert a system operator to a potential voltage collapse? System voltages are low ULTC adjustments fail to change the voltage Reactive power outputs approaching maximum All the Above

All the Above.

Which action (s) does a Reliability Coordinator have the authority to direct all reliability entities within its area to take to return the system to a reliable state. Re-dispatch generation Re-configure transmission Reduce load All the Above

All the Above.

Two generating units are operated in parallel. Generator A is 500 MWs with a droop setting of 3%, and Generator B is 1000 MWs with a droop setting of 6%. Which generator will have the greater response to a frequency drop on the system? Generator A will respond more. Both generators should respond the same. The response would be determined by the Frequency Bias Setting. Generator B will respond more.

Both generators should respond the same. As the droop setting is increased, the response of the unit decreases. Also, larger units will respond more than smaller units with the same droop. Droop % is the frequency change that will cause the unit to run full range of its capacity. In other words, Generator A would respond full range (500 MWs) for 3% change, or 1.8 Hz. Generator B would respond full range (1000 MWs) for 6% change, or 3.6 Hz. From this we can see that both generators will respond with approximately 28 MWs per .1 Hz change in frequency.

An 800 MW generator trips in a Balancing Authority external to your Balancing Authority Area. Which of the following indications would you expect to see in your area? Frequency would drop, and ACE would remain relatively unchanged. ACE would drop to approximately -800 MW. Net Actual Interchange would decrease significantly. Frequency would drop, and ACE would increase significantly.

Frequency would drop, and ACE would remain relatively unchanged. Since the disturbance is external to the BA, ACE should change very little. The Net Actual Interchange would increase as the natural frequency response of the BA allows it to provide assistance to the Interconnection in arresting the frequency drop. The Frequency Bias portion of the ACE equation assists by canceling out the increase in ACE caused by the Net Actual Interchange increasing, assuming the Bias is set correctly.

When a Balancing Authority has exhausted options and can no longer provide its customers' expected energy requirements, what can be used to obtain needed capacity and energy? Energy Emergency Alerts Demand Alert Imbalance Event Capacity Warning

Energy Emergency Alerts. EOP-011 Emergency Operations, Energy Emergency Alert (EEA) process.

Which type of emergency condition is due to not being able to meet the load requirements of an entities retail customers? Load Shed Capacity Emergency System Operating Limit Energy Emergency

Energy Emergency.

A condition when a Load-Serving Entity has exhausted all other options and can no longer provide its customers' expected energy requirements is referred to as ____________? Energy deficiency Energy shortage Load shortage Energy Emergency

Energy Emergency. A condition when a Load-Serving Entity has exhausted all other options and can no longer provide its customers' expected energy requirements. - NERC Glossary of Terms Used in Reliability Standards

When a Reliability Coordinator refers to a GMD, what is being referred to? General Modeling Display Geo-Magnetic Disturbance Ground Modeled Distribution Generation Monitoring Device

Geo-Magnetic Disturbance. Geomagnetic disturbances (GMDs) are naturally occurring phenomena that have caused severe operating problems for power systems. GMDs are disturbances to the earth's magnetic field that are a consequence of energy disturbances on the sun. When solar (sun) disturbances occur, currents may be induced in the earth's surface. EPRI 9.6

A 230 kV transmission line makes contact with a tree as a result of heavy transfers and flashes over to the tree causing the transmission line to relay out. What type of fault is this classified as? Differential Fault Overvoltage Fault Ground Fault Positive Sequence Fault

Ground Fault. EPRI Power System Tutorial

If you remove a parallel transmission line from service to relieve an IROL or SOL violation, what will happen to the loading on the remaining transmission facilities? Decrease Voltage will increase on these lines Probably stay the same Increase

Increase. Transmission application: If you remove a parallel transmission line from service for any reason, the loading on the remaining transmission facilities will increase. The load/demand for electricity will cause the power to flow from source to sink through multiple paths. Equipment outage will cause power flow to shift to other transmission lines.

In performing its reliability analysis, a RC identifies a potential reliability problem. What action should the RC take? Drop Load. Initiate a conference call with impacted entities. Reduce Voltage. Initiate a conference call with all TOP's in the interconnection.

Initiate a conference call with impacted entities. NERC Standard IRO-001: Each Reliability Coordinator shall act to address the reliability of its Reliability Coordinator Area via direct actions or by issuing Operating Instructions. NERC Standard IRO-008: Each Reliability Coordinator shall notify impacted entities identified in its Operating Plan(s) as to their role in that plan(s).

Which of the following best describes the Load/Frequency Relationship? As frequency increases, load decreases. Load magnitude varies with system frequency. Only non-motor loads are affected by a change in system frequency. Load magnitude is independent of the system frequency.

Load magnitude varies with system frequency. As a rule of thumb, a 1% drop in frequency will result in a 2% drop in load. - EPRI Power System Tutorial

In a Power System, cold load can best be described as which of the following? Load at an ice plant Load that is not factored into the interchange transaction Load that has been shed Load that has been de-energized for an extended period

Load that has been de-energized for an extended period. Transmission Operator is primarily responsible for developing and maintaining a restoration plan to reestablish its electric system in a stable and orderly manner in the event of a partial or total shutdown of its system. The restoration Plan should consider the impact of cold load pickup. The NERC Electric System Restoration Reference Document states, "Restoring customer load to service, which has been disconnected for some time, presents new challenges. The disconnected load will probably be much higher than its value at the time of interruption. The simultaneous starting of motors, compressors, etc., will cause high peak demands for power. These higher than usual load requirements are commonly referred to as cold load pickup. Cold load pickup can involve inrush currents of ten or more times the normal load current depending on the nature of the load being picked up. This will generally decay to about two times normal load current in two to four seconds and remain at a level of 150% to 200% of pre-shutdown levels for as long as 30 minutes. When restoring load, sufficient time must be allowed between switching operations to permit stabilizing the generation."

You have just placed a line in service and the receiving bus end of the line shows zero voltage, but there is indication of current flow. What is your primary concern? The low voltage at the bus. A potential voltage collapse. Loss of synchronizing capability. Loss of primary protection.

Loss of primary protection. With the given indications, it is most likely due to a failed potential transformer, or PT. If this is the case, voltage input to distance relaying (primary protection) is also lost since those relays use the voltage input to determine impedance.

A System Operator identifies a transmission line that is operating at 100% of its SOL. What should be done? De-energize the line. Monitor for necessary action. Reduce line voltage. Immediately reduce the loading.

Monitor for necessary action. Transmission Operations application: In this case, the transmission line is at its SOL. As long as the System Operator closely monitors the line and is prepared to take action then no corrective action is needed as long the limit is not exceeded. The question does not offer information related to how the line is trending or the N-1 impacts.

Two lines of the same construction are both connected to Bus A and are both open at the other end. Line #2 is twice as long as Line #1. The voltage at the open end of Line #1 is 3% higher than the voltage at Bus A. What can you conclude about the voltage at the open end of Line #2? 3% higher than Bus A. More than 3% lower than Bus A. More than 3% higher than Bus A. 3% lower than Bus A.

More than 3% higher than Bus A. Voltage at the open end of a transmission line will increase due to an effect called Ferranti Rise. If two lines have the same construction but different lengths, the longer line will produce a higher voltage at the open end compared to the shorter line. The Ferranti rise effect is a long term overvoltage condition that is associated with high voltage lines that have their receiving ends open. Overvoltages greater than 10% above nominal can easily occur. The magnitude of the overvoltage depends on the length of the open-ended line and the strength of the system tied to the closed-end of the line. EPRI 5.3.2.

Early in the day, a BA with several units offline anticipates a capacity shortage during the afternoon. What should the BA consider first? Postpone or cancel unit maintenance where practical. Curtail demand side management customers immediately. Drop load immediately. Implement voltage reduction procedures immediately.

Postpone or cancel unit maintenance where practical. A Balancing Authority anticipating an operating capacity or energy emergency shall perform actions in their Operating Plan which should include, bringing on all available generation, postponing equipment maintenance, scheduling interchange purchases in advance, and being prepared to reduce firm load.

A Balancing Authority with several units offline anticipates a capacity shortage during the afternoon peak due to unseasonal temperature forecast. What should the BA consider first? Drop load Curtail interruptible customers Postpone or cancel unit maintenance Implement voltage reduction procedures

Postpone or cancel unit maintenance. All listed actions may be appropriate at some point if the capacity shortage develops. However, the question asks what should be done first, and postponing outages would be the correct answer.

Interchange Schedules must begin and end at times agreed to by ___________________________. Sending and Receiving Balancing Authorities and Transmission Service Providers Sending and Receiving Balancing Authorities and Transmission Operators Source, Sink, and Intermediate Balancing Authorities Source and Sink Balancing Authorities and Purchasing Selling Entities

Source, Sink, and Intermediate Balancing Authorities. NERC Standard INT-006: For each Arranged Interchange that is transitioned to Confirmed Interchange, the Sink Balancing Authority shall notify the following entities of the on-time Confirmed Interchange such that the notification is delivered in time to be incorporated into scheduling systems prior to ramp start as specified in Attachment 1, Column D: 5.1. The Source Balancing Authority, 5.2. Each Intermediate Balancing Authority, 5.3. Each Reliability Coordinator associated with each Balancing Authority included in the Arranged Interchange, 5.4. Each Transmission Service Provider included in the Arranged Interchange, and 5.5. Each Purchasing Selling Entity included in the Arranged Interchange.

The transmission system must be operated so that instability, uncontrolled separation, or cascading outages will not occur as a result of the most severe single contingency AND Specified multiple contingencies All multiple contingencies External disturbances System operating violations

Specified multiple contingencies.

A System Operator in Balancing Authority "A" has just been directed by the Reliability Coordinator to modify an existing Interchange schedule for an imminent reliability-related reason. Who is responsible for submitting the modified Arranged Interchange reflecting the modification and how long do they have? The Balancing Authority within 30 minutes of the event. The Reliability Coordinator within 60 minutes of the event. The Balancing Authority within 60 minutes of the event. No tag is needed because it is an emergency transaction.

The Balancing Authority within 60 minutes of the event. INT-010 Interchange Initiation and Modification for Reliability. Each Sink Balancing Authority shall ensure that a Reliability Adjustment Arranged Interchange reflecting a modification is submitted within 60 minutes of the start of the modification if a Reliability Coordinator directs the modification of a Confirmed Interchange or Implemented Interchange for actual or anticipated reliability-related reasons.

Which of the following Dynamic Schedules must have a modified tag? The Dynamic Schedule is 200 MW and the hourly integrated value is 230 MWH. The Dynamic Schedule is 100 MW and the hourly integrated value is 120 MWH. The Dynamic Schedule is 300 MW and the hourly integrated value is 320 MWH. The Dynamic Schedule is 275 MW and the hourly integrated value is 300 MWH.

The Dynamic Schedule is 200 MW and the hourly integrated value is 230 MWH. NERC Standard INT-004 R2. The Purchasing-Selling Entity that submits a Request for Interchange in accordance with Requirement R1 shall ensure the Confirmed Interchange associated with that Dynamic Schedule or Pseudo-Tie is updated for future hours in order to support congestion management procedures if any one of the following occurs: 2.1. For Confirmed Interchange greater than 250 MW for the last hour, the actual hourly integrated energy deviates from the Confirmed Interchange by more than 10% for that hour and that deviation is expected to persist. 2.2. For Confirmed Interchange less than or equal to 250 MW for the last hour, the actual hourly integrated energy deviates from the Confirmed Interchange by more than 25 MW for that hour and that deviation is expected to persist.

Each Reliability Coordinator shall include within its operations training program, system restoration training for its System Operators, that includes system restoration drills, exercises and simulation with Transmission Operators. How often must system restoration drills, exercises or simulation occur? Every two years Relief Annually Two per calendar year

Two per calendar year. EOP-006 System Restoration Coordination, The Reliability Coordinator receives restoration plans from its Transmission Operators and develops a Reliability Coordinator Area restoration plan. The RC then conducts two System restoration drills, exercises or simulations per calendar year.

If a circuit breaker does not have a synch-check, reclosing relay and has a large standing phase angle across it, how can the system operator know if it is safe to close the breaker avoiding shock torque to the neighboring generators? If the voltage is within +/- 10 % it is OK to close the breaker. Obtain help from the Regional operating committee engineers to advise you. Ask the generator operators to change reactive to a leading power factor and then check the frequency. Use the synchroscope in the substation control room as a guide to show you how to adjust the system to improve the phase angle.

Use the synchroscope in the substation control room as a guide to show you how to adjust the system to improve the phase angle. The synchronizing scope gets its information from the same sources as the synch-check relay. The potential from the line is compared to the potential from the bus. Using a synchronizing scope, the operator must perform the actual closing of the circuit breaker manually, where the synch-check relay will close the breaker automatically.

What is a Generator Shift Factor (GSF)? Use to determine unit commitment and dispatch. Used to determine the amount of flow contribution a change in generation output will impose on a transmission facility. Applied to external Balancing Authorities to know how much of their generation is flowing into your system. Generation that automatically shifts based on load factors.

Used to determine the amount of flow contribution a change in generation output will impose on a transmission facility. NERC Glossary: A factor to be applied to a generator's expected change in output to determine the amount of flow contribution that change in output will impose on an identified transmission facility or Flowgate.

What is the primary cause of low voltage? VAR losses associated with heavy power transfers Insufficient shunt reactors in service Insufficient transmission capacity Insufficient generation

VAR losses associated with heavy power transfers. EPRI 2009 Power System Dynamics Tutorial, Chapter 5

What is the most important consideration in load forecasting? Historic load Weather Generator outages Energy Profile

Weather. The main determining factor in system load is weather. The weather forecast will be input into a Load Forecasting tool that may also use historical load patterns to calculate the most accurate Load expectation to assist the system operators to expected load pattern in meeting the load demand.

A Balancing Authority has twenty units on governor control. The units have different capacities that range from 200 MW to 1000 MW and droop settings from 2% to 5%. The biggest adjustments in megawatt output in response to a frequency disturbance will be provided by units that have _______________. small capacity and small droop setting large capacity and small droop setting large capacity and large droop setting small capacity and large droop setting

large capacity and small droop setting When a generator synchronizes to the Interconnection, it couples itself to hundreds of other machines rotating at the same electrical speed. All generators should have a droop feature added to their governor. This will allow the generators to respond to the frequency deviation in proportion to their size whenever there is a disturbance or load-resource mismatch. What controls a generator's response is the governor "droop setting." The smaller the droop the closer a generator gets to being an isochronous generator. A 4 % droop gives more generator response to frequency variations than a 5% droop. - NERC training document "Understand and Calculate Frequency Response", Section; Droop. Page 5

The effects of a transmission line loaded above its Surge Impedance Load (SIL) are _________________, the line becomes less inductive and the voltage drops. the line becomes less inductive and the voltage increases. the line becomes more inductive and the voltage drops. the line becomes more inductive and the voltage increases.

the line becomes more inductive and the voltage drops. SIL is the MW loading on a TRANSMISSION line at which the line's natural REACTIVE POWER production equals its REACTIVE POWER usage. A line loaded above its SIL will be more inductive than capacitive and absorb MVARs causing voltage to drop.