The IEC 62055-31 standard for prepaid meters covers all the requirements for static electricity meters laid down in the IEC 62052-11 and IEC 62053-series plus additional requirements specific to prepaid meters. These include factors such as timekeeping under various conditions and how to check payment functionality during environmental conditions tests. Special tests are included to ensure long-term operation of the keypad interface and token carrier (card) interface.
Another area of testing specific to prepaid meters is the load switch utilization that cuts off the electricity supply when the customer’s credit is exhausted. This must switch under heavy duties – for instance, during load conditions with different power factors. And it is the load switch that is responsible for the vast majority of failures we see during certification.
Testing brings confidence
This is a major issue for the electricity industry. Unreliable or inaccurate meters could lead to energy retailers losing revenue, or consumers losing their electricity for no reason. Certification is currently optional for this type of meter. For instance, it isn’t yet covered by the European Union’s Measuring Instruments Directive (MID) (but this could change). However, certification does provide confidence that the meter will be accurate and reliable under all conditions. So energy providers and consumers know they are getting what they pay for, and manufacturers have a more saleable product.
KEMA Laboratories is unique in being able to carry out the complete IEC 62055-31 type test program at our own premises, having invested in specially adapted facilities for tests such as the load-switch test. Combined with our independence and in-depth technical expertise, this “one-stop shop” approach streamlines testing and time to market, and gives all parties even greater confidence in the certified meter.