EPR Hazard – Time to Tackle the Hard Issues?

摘要

The fundamental problem discussed by this paper is how NZ should handle EPR situationswith:1. very high EPR (typically > 4kV)2. a very low probability of a hazardous EPR event occurring at any one site3. a very large number of sites (typically > 10,000).If these general types of situations were to be considered an “unacceptable risk” (due to theirvery high EPR levels), the cost of mitigating them would be huge.This paper provides a summary of “how big” current EPR problems are at the locations ofvarious different types of power network plant in NZ. The two potentially “biggest” types ofEPR problems in NZ are identified as:1. concrete power poles, steel power poles, steel power pylons2. rural distribution transformers.The applicable EPR hazard voltage limits in NZ and Europe are discussed, together with therelevant European standards. Differences between European and NZ power systems areoutlined, and used to explain why the European standards are inappropriate for “unqualified”use in NZ.Proposed changes to the current NZ EPR hazard voltages are explained. In particular, theneed for a general Risk Study for each of the:(1) concrete power poles/steel power poles/steel power pylons, and(2) rural distribution transformerssituations is advocated, to determine the best strategy for addressing these situations. Theserisk studies will not only attempt to broadly quantify the risk, but also identify the major riskfactors that make the risk at some locations much worse. This should enable the worstlocations, at the very least, to be identified and addressed.