HV Testing: How hard can it be?

You should know better how to handle High Voltage Testing!

My first adventure with HV testing was when I followed my older colleagues to the University’s HV Lab. I spent the whole time perched on the bar stool next to the control board, while the deafening, “Frankenstein-ian”, cracking and crackling was coming from the capacitors. I held my hands tightly in my pockets, scared that any extension of my limbs would attract the lightning to me. Rationally, I knew I was protected by Faraday’s cage, but the primal fear and common sense, told me that this is dangerous and you need to know what you’re doing.

So, here are the 5 most important things you need to know about HV testing:

★ 1: Standards rule!

The first AC power distribution system using transformers was built in 1886 and the International Electronical Commission held its inaugural meeting on 26 June 1906. Clearly, power supply and standardisation go hand in hand from the beginning. Today, all aspects of HV and MV equipment design and testing is ruled by standards. Make sure you know which ones to apply and when.

★ 2: Tests are potentially destructive!

Standards prescribe amplitude and duration of testing voltages and currents, but these parameters need to be chosen based on the type of equipment, its application and actual service conditions. Don’t assume trial and error approach! If the testing parameters are set too high, testing will damage or even destroy your equipment.

★ 3: Tests must reflect actual operating conditions!

One would assume that it is better to err on safe side. However, if the testing parameters are too low, the equipment may be damaged once installed at your facilities or live a very short life, while trying to keep up with actual operating conditions. Like a true Goldilocks – HV testing must be just right!

★ 4: Calibration is a must!

The easiest way to mess up the testing is to use a non calibrated instrumentation. The only way to be sure that the testing parameters are indeed in line with standard requirements is to be able to trust the measuring equipment. Testing equipment must be calibrated on regular basis, by reputable institutions, or the results would be misleading.

★ 5: It CAN kill you!

Undoubtedly, high voltages in combination with high currents are lethal. Since the HV testing requires these lethal voltages to be fed into the equipment, strict testing procedures must be respected to prevent harm from dangerous voltages. Furthermore, HV equipment must be designed to protect the operator and the testing must appropriately confirm equipment’s compliance with safety standards.


Stay safe and contact us if you need experienced consultants for any advice with or representation during HV Testing.


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