PV Systems lesson 6-15

Phase unbalancing

3 phases/ 120 degrees out of phase

articles to know

690 705 706 710 480

Secondary battery definition

A battery that can store and deliver electrical energy and can be charged by passing a current through it in an opposite direction to the discharge current.

Maintenance plan

A checklist of all required regular maintenance tasks and their recommended interval

Maintenance log

A collection of past maintenance records

Stratificaiton

A condition of flooded lead-acid cells in which the specific gravity of the electrolyte is greater at the bottom than at the top.

Charge controller

A device that regulates battery charge by controlling the charging voltage and/or current from a DC power source, such as a PV array

Vibration load

A dynamic structural load due to periodic motion. Building shifting

Live load

A dynamic structural load due to the weight of temporary items and people using or occupying the structure. Temporary

Wind load

A dynamic structural load due to wind, resulting in downward, lateral, or lifting forces. Weather

J-bolt

A fastener that hooks around a secure support structure and has a threaded end that is used with a nut to secure items

combiner box

A junction box used as the parallel connection point for two or more PV array source circuits

electrical inspector

A local official qualified to evaluate electrical installations in the field for compliance with applicable codes and standards.

Tax incentive

A measure to reduce owed taxes as an inducement for investment.

Net metering

A metering arrangement where any excess energy exported to the utility is subtracted from the amount of energy imported from it. One meter (by-directional)

Incentive

A monetary inducement to invest in a certain type of capital improvement, such as an energy-generating system or energy-conservation measure.

Rebates

A one-time refund for a portion of an original purchase price.

Junction box

A protective enclosure used to terminate, combine, and connect various circuits or components together.

Dead load

A static structural load due to the weight of permanent building members, supported structure, and attachments permanent

Troubleshooting

A systematic method of investigating the cause of system problems and determining the best solution.

Diversion load

An auxiliary load that is not a critical system load, but is always available to utilize the full array power in a useful way to protect a battery from overcharge.

intial cost

An expense related to the design, engineering, equipment, and installation of a system. big upfront cost

Hydrometer

An instrument used to measure the specific gravity of a liquid

Hardest to troubleshoot

Battery

Float charging

Battery charging at a low charge rate that finishes the charge and maintains full battery charge by counteracting self-discharge.

Absorption charging

Battery charging following bulk charging that reduces the charge current to maintain the battery voltage at a regulation voltage for a certain period.

Archimedes hydrometer

Bulb type syringe that extracts electrolyte from the battery cell into a chamber

Primary batteries

Can store and deliver electrical energy but cannot be recharged.

common primary batteries

Carbon-zinc lithium

Discharging process

Chemical to electrical

Battery definition

Collection of electromechanical cells that are contained in the same case and connected together electrically to produce a desire voltage

rectifier

Converts AC to DC power

Inverters

Converts DC to AC power

Equalization charging

Current-limited battery charging for a limited time period to a voltage higher than the normal bulk charging voltage in order to bring each cell to a full state of charge.

waveform

DC vs AC. The shape of an electrical signal that varies over time.

Stationary batteries

Designed for occasional deep-discharge, limited cycle service last long time on standby service Commonly used for UPS's to provide backup power to computers. telephone equipment, other critical loads Not recommended for PV systems

Starting, lighting, ignition batteries

Designed primarily for shallow-discharge cycle service many thin plates per cell, allowing high currents for a short period of time used for automobile starters Not recommended for PV systems

charging process

Electrical to chemical

Generators Synchronizing and wiring

Frequency, voltage, phase

Centralized power Plant

Large-scale generation of electricity at centralized facilities usually located away from end-users and connected to a network of high-voltage transmissions

Most common secondary batteries

Lead-acid

Plan Examiner

Local official qualified to review construction plans and documents for compliance with applicable codes and standards

Major battery components

Positive terminal, negative terminal, Battery case, cell vents, positive plate, Negative plate, Active material, separator, cell partition, intercell connector

Multistage charging

Quicker/ does better job includes additional charging modes to reach a higher state of charge

single axis tracking

Rotates on one axis to approximately follow the position of the sun

duel axis tracking

Rotates two axes independently to exactly follow the position of the sun maximizes the amount of the solar energy received

System sizing hardest

Stand alone

Secondary batteries

Store and deliver electrical energy/can be charged by passing a current through it in an opposite direction to the discharge

Soiling

The accumulation of dust and dirt on an array surface that shades the array and reduces electrical output.

Blocking

The addition of lumber under a roof surface and between trusses or rafters as supplemental structural support.

Bulk charge

The battery charging at a relatively high charge rate that charges the battery up to a regulation voltage, resulting in a state of charge of about 80% to 90%.

Dedicated space

The clear space reserved around electrical equipment for the existing equipment and potential future additions.

Work space

The clear space reserved around electrical equipment so that workers can inspect, operate,

over-discharge

The condition of a battery state of charge declining to the point where it can no longer supply discharge current at a sufficient voltage or without damaging the battery.

Sulfation

The growth of lead sulfate crystals on the positive plate of a lead-acid cell.

SOC ( state of charge)

The percentage of energy remaining in a battery compared to its fully charged capacity.

DOD ( Depth of Discharge)

The percentage of energy withdrawn from a battery compared to its fully charged capacity.

overcharging

The ratio of applied charge to the resulting increase in battery charge.The condition of a fully charged battery continuing to receive a significant charging current.

Commissioning

The starting and operation of a PV system for the first time

Renewable energy certificate (REC) "green tags"

Tradable commodity that represents a certain amount of electricity generated from renewable resources

Nickle-calcium battery

Use in critical, low temp applications. High initial cost limits in their PV systems

System sizing easiest

Utility interactive

authority having jurisdiction ( AHJ

an organization, office, or individual designated by local government with legal powers to administer, interpret, and enforce building codes.

Fixed mount

and array mounting system that permanently secures modules in a non-movable position at a specific title angle

Vertical axis (goes with single axis)

changes the azimuth angle or the north/south axis which allows array to follow the sun from east to west

traction batteries (Motive power batteries)

designed for repeated deep-discharge cycle fewer plates per cell thick plates/ very durable/ long life Very popular in PV systems, golf carts, forklifts, hybrid vehicles

Building Integrated

fixed array that replaces conventional building materials with specifically designed modules that perform architectural function in addition to producing power

generators synchronize what

frequency, voltage, phase

Duel metering

he arrangement that measures energy exported to and imported from the utility grid separately. Two meters (import & export)

Easiest to troubleshoot

interactive systems

actual mounts

max voltage code requirements in ARTICLE 690.7. Voltage

Adjustable mount

mounting system that permits manual adjustment to the tilt and/or azimuth

Grants

one-time monetary payment for certain types of projects.

Primary battery definition

primary battery: A battery that can store and deliver electrical energy but cannot be recharged.

Refractive hydrometer (refractometer)

uses a prism to measure the refractive index the the electrolyte related to specific gravity

distribution substations

voltage regulation that delivers electric energy from transmission systems to residential consumers