Resilience of Digital Protection Relay’s Power Supplies to Powerful Nanosecond Pulses

International Journal of Research and Scientific Innovation (IJRSI) | Volume VII, Issue VI, June 2020 | ISSN 2321–2705

Resilience of Digital Protection Relay’s Power Supplies to Powerful Nanosecond Pulses

Vladimir Gurevich
Central Electric Laboratory, Israel Electric Corp.

Abstract – This article suggests the results of attenuation measurements provided by various types of high-quality two-stage electromagnetic filters and offers the best two types. Test results are provided of digital protection relay (DPR) equipped with 316NN63 power supply sources fitted with one of the best filter types. It is also suggested that using these filters in combination with voltage suppressors connected before power supply of high-sensitivity equipment implemented in the power industry can significantly increase its noise-resistance.

Keywords -electromagnetic filters, noise, DPR, digital protection relay, HEMP, Electrical Fast Transient

I. INTRODUCTION

Testing of DPR power supplies’ resistance to electrical fast transient (EFT) and its results were detailed by the author in [1]. The main result was that the majority of participating DPR types were really resistant to all types of test impacts. There was only one that failed to pass the test which was the REC316, manufactured by ABB with 316NN63 power supply. The issue was that some output voltages, and consequently some internal modules, switched off starting from 1 kV amplitude of a standard EFT. Later on, they automatically returned into operational conditions within several seconds upon termination of test pulse impact. It should be noted that the LEDs on the front panel continued detecting the DPR’s status change subject to test pulse impact. An attempt to increase the DPR’s noise-resistance using a special external FN 2090-3-06 filter connected before the power source was not successful.

II. PURPOSE

The range of electromagnetic filters available todayon the market is very broad: there are both quite sophisticated inexpensive two-stage filters with fair specifications and very simple and cheap filters. These high-quality filters cost 10–40 US Dollars and even cheaper (made in China). The choice is complicated by the fact that various manufacturers use different methods and equipment to measure filter parameters and provide promotional or even erroneous information (discovered by the author) in their specifications. This necessitated conducting comparative trials of the best filter samples from the leading manufacturers under the same method and using the same equipment, and then testing REC316 DPR with 316NN63 power source in combination with the best filter sample. The DPR with the above-mentioned power supply is a good indicator of EFT impact and thus, filter efficiency can be estimated based on its response.

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