An approximation method for the calculation of active and reactive installation errors from individual transformer test errors


Conference: Metering, Billing, CRM/CIS Australia and New Zealand 2005.
Location: Melbourne
Presenter: Vic Church
Abstract: The calculation of total metering installation errors from the known errors of the individual components has been carried out for many years. Before computers manual calculation sheets were used that provided a good approximation, however they were either restricted to real energy or required a fairly tedious calculation process. With the advent of computers it has been possible to produce accurate calculators that are easy to use.

For organisations that have not purchased or written calculators this paper shows a simple method for the derivation of approximation formulae that enable the calculation of installation errors at the test points required by the National Electricity Code. By using the same procedure formulae may be derived for any test point. An advantage of using this method is that it can easily be seen which error has the most effect on the total installation error and where compensation can best be applied. The formulae are simple to use and the calculations can be carried out using only a four function calculator.

Although this is an approximation method, comparison to the true results indicate that for all practical purposes the difference is minimal.