Application Note

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Application Note

From the Fluke Digital Library @ www.fluke.com/library

Troubleshooting

photovoltaic systems:

three typical problems

With the energy situa-

tion and problems in the

last few years has come

a major effort to increase

the amount of energy from

renewable resources. State

and federal government

policies in many areas

mandate increased use

of solar power. An HVAC

technician who is servic-

ing other equipment in the

building might encoun-

ter solar power systems.

Because the concepts and

arrangements of these

systems are new to HVAC

technicians, a short over-

view of the systems and

components is in order.

Photovoltaic systems convert

sunlight (photo) into electrical

power (voltaic). The sunlight that

strikes the semiconductor mate-

rial in the individual cells causes

electrons to move through a

wire. The electricity gener-

ated by photovoltaic systems

can be used to run a range of

equipment, from domestic appli-

ances to commercial production

equipment.

There are a number of vari-

ables in a PV system, but

ordinarily the PV array is

mounted on a roof that faces

the south as much as possible.

Obstructions are avoided. Note

that less power will be gener-

ated in the winter than the

summer due to the shorter days.

Also, maximum power will be

generated at midday rather than

in the morning or evening.

As part of the PV installa-

tion, some facilities provide a

real-time computer display that

shows the amount of energy

produced by the PV display, the

dollars saved, and the amount

of fossil fuel usage avoided. It is

great to know that facilities are

increasingly leading the way to

energy independence and low-

ering the amount of pollutants

released into the atmosphere!

The electricity generated by a

PV system may be used imme-

diately by that facility, stored, or

By Ron Auvil

in some cases sold back to the

local electric utility.

It is only natural for facilities

that have PV systems installed

to expect HVAC technicians to at

least know the basics. As these

systems become more com-

monplace we may be expected

to perform some basic trouble-

shooting of them.

Components of a PV

system

PV systems consist of the follow-

ing general components:

Individual cells. An indi-

vidual cell is a small part of a

PV system. A cell consists of

the semiconductor material, a

support structure, and a trans-

parent material that allows the

With the push to energy independence and renewable

energy sources, HVAC technicians need to know how

to troubleshoot photovoltaic systems

This electrical conduit connects a series of solar cell arrays.

Summary of content (4 pages)

PAGE 1
Troubleshooting photovoltaic systems: three typical problems Application Note By Ron Auvil With the push to energy independence and renewable energy sources, HVAC technicians need to know how to troubleshoot photovoltaic systems With the energy situation and problems in the last few years has come a major effort to increase the amount of energy from renewable resources. State and federal government policies in many areas mandate increased use of solar power.
PAGE 2
sunlight to strike the semiconductor material. The cell must be physically tough as it is exposed to the weather. The transparent material that covers the cell also must be stain and dirt resistant. Each individual cell produces only a few watts of electricity. Modules and arrays. A module consists of a number of cells connected together side by side. Modules may be in either series or parallel, as needed to obtain the desired voltage and current.
PAGE 3
To measure the current output of this photovoltaic cell, a technician wraps the 381 iFlex ™ flexible current probe around the conductor. When you get up on the roof, visually check the entire system for any obvious damage. Also, keep in mind that someone may have disconnected the wiring accidentally while servicing another device on the roof. Once the module or array that is not producing power is found, check all wiring, switches, fuses, and circuit breakers.
PAGE 4
indicates current inverter and system performance. Remember that the 381 clamp meter produces a true-rms reading; you can use the voltage and current to measure and record the kilowatt (kW) output. If possible use the inverter display to show the current total kilowatt hours (kWh). You can then write down this value and compare it to the one recorded during the last inspection.