The aim of this project is to:
- define one or more sets of parameters to characterise lightning impulses
- write a report in which the relevancy of the proposed parameters are explained
- establish unambiguous algorithms to calculate these parameters
- write a proposal for the relevant parts of IEC 60060-1 and IEC 61083-2.
State of progress
In the first work package of this project the current problems among manufacturers, test laboratories and calibration laboratories were inventorized. It appeared that the problems are even greater than the project team had expected. Also a literature investigation was made, in the literature written in the last 10 years little information could be found about this subject. In the second work package (investigation towards the relevancy of the conventional and new parameters) a software package to evaluate both the conventional parameters as well as some new ones was developed by one of the partners. The software was tested with analytical and actual measuring data and the software showed good results. For the test purposes a special generating circuit was designed. Simulations with this design were performed and they showed good results. The project team decided to use this design and the generating circuits are being built. Also a test procedure for the determination of the influence of overshoot, oscillations and some other parameters was designed. Actual testing on specimens is finished and some ideas for new parameters and their calculation method will be proposed to international bodies to be placed in standards. To inform others about this project several papers have already been published and presented. It is know that in the near future papers will be published.
Experts in high-voltage and high-power testing have recognised that, when analogue measuring equipment was replaced by digital measuring equipment, several problems arose in the automized evaluation of test voltages such as lightning and switching impulses. The major problem right now is that the rules for the evaluation of impulse parameters as described in several standards (e.g. IEC 60060-1) are ambiguous when using digital evaluation. When using analogue measuring equipment the evaluation of the impulse parameters is limited because the evaluation has to be done manually. The change from analogue to digital measuring techniques removes this limitation. From this it follows that it is appropriate to make an investigation towards the introduction of new parameters. The introduction of new parameters or maintaining the existing parameters can only be done with a sound physical fundament. Therefore the relevancy of parameters which characterises lightning impulses, with their new definitions chosen, have to be proved by performing breakdown tests.
In order to be able to achieve the above mentioned objectives a project planning has been made and the project has been divided into four workpackages. Each partner has several tasks in each workpackages. The four workpackages are: 1) preparation phase (gathering of information), 2) test phase (first algorithms), 3) evaluation phase (definitive parameters) and 4) result phase (proposal for standard)
Funding SchemeCSC - Cost-sharing contracts
KT22 7ST Leatherhead