All posts by LaoRen

Low temperature meter reliability test

Accelerated Life Test for Energy Meters

There are several ways to predict the reliability of an energy meter. The International Electrotechnical Commission (IEC) provides a series of standards related to reliability and dependability tests or evaluations.

Applicable are

  • IEC 62059-11 - general concepts
  • IEC 62059-21 - collection of meter dependability data from the field
  • IEC 62059-31-1 - accelerated reliability testing
  • IEC 62059-41 - reliability prediction

The method described in IEC 62059-41 is a white box method. The calculation of the failure rate this way is done with a theoretical approach. Several accredited testing laboratories offer to review and certify the evaluation performed by the manufacturer.

The manufacturer calculates the failure rate according to this method, as he is the only party able to do this. The testing laboratory will review the calculation and method. Calculations that meet the requirements will be awarded with a certificate.

The method for reporting and calculating the failure rate is up to the manufacturer. Most important is that it meets the requirements of IEC62059-41.

Controller for temperature
CLOU environmental lab temperature controller
Low temperature meter reliability test
Low temperature meter reliability test

pictures are taken from running tests in the environmental section of our ISO17025 accredited type test laboratory

Beside of theoretical analysis another approach is to test the reliability and functionality of the meters inside a climatic chamber for a duration of 8...12 weeks.
The climatic chamber follows a certain profile for temperature and humidity while the meters inside are energized with a profile varying from nominal load to maximum load.

Before and after this test the meter is verified for functionality and accuracy. Still this test can not cover all aspects of the annual drift.

We deliver the sources for doing these tests and can take care about integration into the climatic chamber. The test procedure itself has to be defined together with the meter manufacturer. We can make suggestions based on best practice.

Thanks for reading.


Multi Secondary Voltage Transformer

Multi Secondary Voltage Transformer MSVT

Single phase meters with closed I-P links require galvanic isolation for testing. This galvanic isolation is done by a Multi Secondary Voltage Transformer (MSVT). The MSVT has one secondary taping for each single phase meter under test.

The CLOU CL6202-xx can be configured for various secondary tappings. For requests please indicate the no. of meter positions.

item value
No. of windings max. 48
Primary voltage 220 V  –  240 V
Primary frequency 50 Hz  –  60 Hz
Secondary voltage 220 V  –  240 V
Range of secondary burden 4 VA – 15 VA
Accuracy Error prim/sec ≤ ± 0,1%
Phase Error prim/sec ≤ ± 2 min
Accuracy Error sec/sec (within burden range) ≤ ± 0,01%
Phase Error sec/sec (within burden range) ≤ ± 1 min

Each secondary tapping is calibrated individually.
Please contact us for more information.