Specialist cable manufacturer Tratos Cavi has recently completed the construction of a Faraday Cage test site at the company’s headquarters in Pieve Santo Stefano, Italy.
Measuring 24 x 16m and standing at 14m high, the new Faraday Cage enables Tratos to effectively administer AC Resonant Tests on-site, allowing testing of up to 220kV of nominal voltage cables and up to 20km of medium voltage cable.
AC Resonant Testing is now the standard method of testing higher voltage cables. However, it is vital that AC Resonant tests are carried out in a controlled environment, and this is exactly what the new Faraday Cage provides.
The facility incorporates a new innovative locking system to ensure perfect shielding from any sort of external interference. Inside are sophisticated tools for testing and an adjustable high voltage reactor which, together with the exciter and the regulator, comprise the heart of the system.
The reactor is insulated in oil and consists of two identically wound high voltage coils mounted on a platform, with a motorised drive mechanism providing variable air gaps. Its upper part includes space for oil expansion and it offers 12MW of resonance power, allowing three taps of 350kV, 150kV and 70kV. The exciter section is mounted in a separate oil filled steel tank and contains a single phase, step-up transformer which supplies the AC voltage required for the resonant circuit. The regulator provides an adjustable input voltage to the exciter and controls the input voltage of the reactor.
This sophisticated equipment can detect even very low levels of picocoulombs and is governed by a modern control system incorporating a Programmable Logic Controller (PLC), which is designed for multiple inputs and output arrangements, immunity to electrical noise, and resistance to vibration and impact. This allows precise measurements to be recorded, ensuring Tratos meets industry standard ISO 9001, and that Tratos is approved by BASEC.