Substation Panel Wiring and Wiring Checks
During the commissioning of modern electrical power systems, like substation or industry environments, there are literally hundreds of connections that have to be verified. Next to the instrument transformer wiring, there are also logic signals, trip and control signals to breakers, different auxiliary signals and supply from the station battery and grid power.
Wiring problems, like the wrong polarity of a voltage or current transformer path, are one of the most common errors in electrical power systems.
Having the right equipment and the right procedures can substantially speed up those tests while improving personal safety at the same time.
Literature
Expert recommends
COMPANO 100 + CPOL3
Our mobile, battery-powered test set COMPANO 100 is the ideal solution for all kinds of wiring checks, where AC and DC voltages and currents are required. With a DC-free sawtooth signal, which you can use in combination with the hand-held CPOL3 polarity checker, the wiring of instrument transformers can be checked without the risk of magnetizing them.
The COMPANO 100 Advanced Package includes all accessories required for this application as well as the software licenses.
Optimized for the field technician
Mains-independent operation
As a battery-powered test set, you can use COMPANO 100 even before a new substation is energized. Mains power is often installed in parallel with wiring checks and therefore not fully available, with COMPANO 100 there is no need for a portable generator.
Lightweight, portable test set
Due to its low weight of less than 10 kg/22 lbs, you can easily move COMPANO 100 from one test location to another. This saves you a lot of time, especially during wiring checks, and it increases your safety by avoiding tripping hazards due to long extension leads.
Electronically controlled sources
COMPANO 100 uses electronically controlled current and voltage sources. With these high accuracy signals you can check the wiring and the correct measurement of protection relays, meters, short-circuit indicators or modern SCADA systems at the same time.
High power output
With up to 110 A AC, COMPANO 100 lets you perform wiring checks with primary injection on current transformers. Adding the optional voltage booster VBO4 even allows you to use primary injection on voltage transformers or sensors requiring higher voltages of up to 750 V AC.
Handheld polarity and wiring checker
CPOL3 allows you to easily perform measurements without a cable connection back to the test set. Just hold it in your hand, place it on an electric cabinet with its removable magnetic backside or use it like a pen-style meter, with the included measurement tip.
Polarity checks with current clamp
You can use CPOL3 together with a current clamp to conveniently measure the polarity of the test current flowing through the wire at any location along the wire.
Perform multiple test steps with a single tool
CPOL3 combines the functions of several devices in one. There is a true RMS voltage display that makes it possible to assess the burden. AC or DC detection, which helps to detect additional wiring faults. The ""oscilloscope"" mode to graphically display the waveform, and a ""LoZ"" with low input impedance to suppress coupled signals.
The smart system to check polarity and wiring
CPOL3 can be used in combination with one of our test sets, such as COMPANO 100, CMC 353 or CMC 356, to easily combine several aspects of wiring testing.
The test set is used to inject a saw-tooth test signal into the primary or secondary side of the CT or VT. CPOL3 displays a smiling green face if the polarity is correct. The signal can also be displayed in ""oscilloscope"" mode. In this case, a sawtooth waveform appears, rising quickly and falling slowly.
In the diagram beside, there is a wiring error on the secondary side. The wiring error results in reverse polarity and CPOL3 shows a sad red face on the secondary side. The wrong polarity is also visible by the inverted signal in the oscilloscope mode. In addition to the polarity, CPOL3 also displays the measured voltage. The closer the measurement is to the burden, the lower the loop impedance and the lower the displayed voltage. This means that the terminal assignment can be easily checked by comparing the voltage, and the burden can also be roughly determined.
1: Test set | 2: Test switch | 3: Burden
The problem of current transformer core magnetization
Polarity checks are still often carried out with a battery and an analog voltmeter. This is done by briefly injecting power from the battery on the primary side and checking for either a positive or negative deflection on a voltmeter, connected to the secondary side. Though it’s a quick and simple method, it has one key disadvantage: The direct current from the battery magnetizes the current transformer core over time. The demagnetization that’s then necessary is rarely performed in practice. In a fault scenario, the magnetized transformer reaches saturation too soon and distorts the current on the secondary side, this can result in protection system malfunctions, which can lead to costly failures.
COMPANO 100 offers a DC-free sawtooth signal for wiring checks, which avoids this problem. This signal can then be detected with CPOL3 to check the polarity along the entire path from the current transformer to the relay.
Wiring checks at National Grid US
Interested in how one of our customers used the COMPANO 100 and CPOL2 (the predecessor of CPOL3) for the commissioning of a new
substation in upstate New York?
CPC 100 + CPOL3
The CPC 100 primary test-set can be used for wiring checks on current and voltage transformer wiring with primary injection for high test currents and voltages.
It can also generate the sawtooth polarity check signal for the handheld polarity checker CPOL3.
CMC 310 + CPOL3
Our CMC devices focus on protection testing, but all them can also be used for wiring checks. Both operating options, CMControl as well as Test Universe, support the output of voltages, currents, and the CPOL polarity check signal needed for this application. The CPOL2 handheld polarity checker is required for testing CT and VT paths.
