The grounding of a high-voltage electrical system helps to ensure the safety of personnel. Voltage rises in the neighboring area of electrical systems, caused by a system fault or lightning, can be extremely dangerous.
Conventional test solutions, which use power system frequencies, need enormous power and complicated methods to overcome the problems of interference. Varying the frequency and using narrowband digital filtering with the Omicron CPC 100 Multi-functional Primary Test System and CP CU1 reduces the required power and the equipment weight to a minimum.
Using the current-voltage method, the challenge for good ground impedance (Zgrid) measurements is to inject sufficient measurement current into the soil at a remote location and to measure the voltage rise caused by this injection – and not by any other current in the ground.
The CPC 100 and CP CU1 test system meets this challenge. It injects current at non-network frequencies into the soil at a remote station via the existing power lines. It then selectively measures the voltage rise at the used frequencies.
The measurements are performed according to international standards including DIN VDE 0101, CENELEC HD637S1, IEEE Std 80-2000 and IEEE Std 81-1983.
The step and touch voltages (Vstepand Vtouch ) of the local station can be measured with the CPC 100 itself or more conveniently with the HGT1 – a frequency selective voltmeter which minimizes wiring.
Ground system analysis
• G round grid impedance for large systems up to 100 A | with CP CU1
• Step and touch voltage up to 100 A | with CP CU1 and HGT1
• Ground grid impedance for small systems up to 6 AAC
• Soil resistivity up to 6 AAC
• Integrity check of grounding connection up to 400 ADC
• Reduction factor / current split factor
• Measure multiple current paths with Rogowski coil
This is part of the Omicron CPC 100 All-In-One Test System Series. Check out the other posts!