Finding test space
Traditionally, though not official sanctioned by standardization documents, a distinction is made between low, medium and high voltage. Low voltage (everything below 1 kV) is the domain of consumer, commercial and industrial utility voltage levels, medium voltage (1 – 52 kV, a rather arbitrary range) belongs to the distribution of electrical energy whereas high voltage is the realm of transmission.
In the first decades of KEMA Laboratories, testing was basically centred around a single low or medium voltage object. Severe challenges had to be faced with regard to the rapid increase of the voltage and power involved during the decades of power grid expansions in the fifties to seventies. At the opening of laboratory 2, in 1938 His Royal Highness Prince Bernard of Orange was shown a unit of a 380 kV airblast breaker in a test bay. Still, at KEMA the majority of power testing was on medium voltage distribution equipment.
In 1965, laboratory 3 was constructed for low voltage AC and DC. This laboratory, however, had a short life time. It was decommissioned in 1976 after that a number of 80 kA tests had been carried out of compressed air switches which were intended to interrupt the ultra-high DC current in the coils of the European nuclear fusion project JET in the UK. After the acquisition of laboratories in Chalfont, USA and later Prague low-voltage and DC testing returned into KEMA Laboratories’ portfolio in the nineties.
Under the influence of the market, and the need for more test bays to accommodate more and bigger test objects a next generation test laboratory was realized in 1973: laboratory 4. The years that came were tense, for soon after the commissioning there was an international epidemic of mergers among laboratory 4 customers. The testing, however, continued and new plans were made. The first big one was laboratory 5 opened in 1980. By that time the synthetic test circuits at KEMA left the experimental phase and were put into commercial operation bringing higher voltage levels within reach. As a result of this new installation the number of orders increased by 20%. Thanks to these new test sites, tests could be realized that could have been performed nowhere in the world before. There was much interest from the Far East: India, China, Japan, whereas the US market declined. In 1980 already tests were performed for 21 countries.
Now the situation arose that most medium voltage tests were carried out in laboratory 2 while the high-end synthetic testing were carried out in the new laboratories 4 and 5. Owing to the market situation, it was decided to decommission laboratory 2, with the last test shift on 28 January 1993.
In the meantime, laboratory 4 was prepared for medium voltage test. A 36 kV load installation was installed in the central part of the laboratory, accommodating all the reactors and resistors needed for the typical medium voltage load switching tests. But already quickly, the market of both high- and medium voltage testing swung up again, and plans were made for a dedicated MV laboratory. Commercially, it is not wise to occupy the large halls of laboratory 4 and 5 with the small medium voltage objects, when the same site can be used for high-voltage equipment. The idea was to recycle as much as possible components from laboratory 2 and to be able to operate independently from and parallel to laboratory 4 and 5. The laboratory 2 generators were no longer used, so connection was established to supply power from up to two of the existing four generators. But the laboratory 2 transformers could: after thorough inspection and overhaul, four of them started a second life in laboratory 6.
In 2001, laboratory 6 opened its doors, with the “decoration” of an art work by having paint sprayed by the laboratories founding fathers, M. de Vries, G. Hoekema and H. Kempen. After a few years of thin business, soon this laboratory became very successful commercially, offering the opportunity for full power testing of equipment up to 40.5 kV at the same time freeing up high-voltage space in the bigger laboratories. Moreover, Laboratory 6 became a breeding ground for novice test-engineers: under the guidance of experience engineers, several generations mastered the complicated three-phase phenomena involved in testing.