It is a very important question: how durable is a particular measuring instrument? And how stable are the measurement results over a long period of time? With the upcoming massive roll out of smart metering throughout Europe, this is a particularly crucial issue which is often raised by end users.
Testing in accordance with IEC 62059-32-1
The IEC standard 62059-32-1 provides guidance on this topic. This document describes a test for examining the stability of an electricity meter. In basic terms, some samples are exposed to the maximum operating temperature for a period of 1,000 hours. During this period of time, the maximum current flows through the meters. The meters undergoing the test are consequently subject to stress levels at their maximum operating conditions.
A comparison is made before and after the test to determine whether the accuracy of the meters has been affected as a result of the durability test. The meters are also checked on a regular basis during the test.
Testing at NMi
At NMi, we have developed a specific test setup to perform this test. The test setup consists of a climate chamber in combination with a separate power supply for polyphase loads up to 120 A. This power supply is operated in parallel in order to run several durability tests at the same time at different loads. For meters capable of measuring both active and reactive energy at the same time, the power factor is set at cos φ = 0,866 in order to properly assess both measurement methods.
By testing in accordance with the 62059-32-1 standard, NMi can offer you added safety in checking the durability aspects. Therefore more ease of mind for your products with the upcoming massive smart meter roll out.