The need for greater standardisation in utility power quality measurements

摘要

The methodology and reasoning behind power quality monitoring by electricity utilities has undergone large scale changes in the past several years. In the past, power quality monitoring has been carried out in a reactive manner; that is, as a result of a specific problem and was usually only conducted in a localised area. Power quality monitoring instrumentation developed to suit fault finding applications and in many cases design was based upon customer requirements rather than a standard specification. While fault finding is still an essential facet of power quality monitoring, the fact that regulatory authorities are now taking an interest in power quality has meant many electricity utilities are now taking, or indeed are forced to take a more proactive approach to power quality monitoring. This type of monitoring requires different characteristics in a power quality instrument. It is necessary to have standardised instrumentation which can be left in the field over long periods of time. For many years there has been no specific international or Australian standard which outlines the way in which power quality disturbances should be monitored or how power quality surveys should be conducted. IEC standard 61000-4-30 goes some way towards solving this problem detailing how various power quality parameters should be measured and recommending minimum survey periods. The paper examines some of the issues in routine power quality monitoring. Special emphasis is placed on issues pertaining to measurement standards and measurement techniques. The paper incorporates the experience gained and problems encountered by the Integral Energy Power Quality and Reliability Centre in carrying out power quality surveys.