Payment meters are used in situations where the supply of electrical energy to the load may be interrupted or its restoration enabled under the control of the payment meter in relation to a payment tariff agreed between the customer and the supplier.
The functions of a payment meter are to measure electrical energy consumed and to decrement the available credit value in accordance with the metered consumption, and possibly in accordance with the passing of time. When the available credit value has been decremented to a predetermined value that is related to the payment mode in use, a switch is used to interrupt the supply to the customer’s load.
Besides the metrological accuracy requirements, the correct operation and safety of additional functions like source and or load switching and time keeping become crucial. For this reason, IEC TC13 developed the IEC 62055-31 for electricity metering with payment systems and the IEC 62054-21 for tariff and load control. These standards add specific payment energy meter requirements to the existing generic IEC 62052 and IEC 62053 series of energy meter standards. Examples are requirements for the token carrier interface, source and load switches, time synchronization and functional requirements for the robustness of the meter accounting process.
KEMA Labs is now ISO 17025 accredited by the national Dutch accreditation council for all testing activities required to prove compliance with the IEC 62055-31 and IEC 62054-21 standards.
To this end, KEMA Labs has set up various test facilities, including a laboratory where tests with high currents of up to 10,000 amps can be carried out to test the source and load control switches. Endurance switching tests at different power factor values as well as short circuit current making, carrying, and breaking tests can be performed.
The correct operation of the internal switches and of the time synchronization is to be verified during all kind of external conditions like electromagnetic disturbances (EMC), different power quality phenomena and change in temperature and humidity. All necessary tests and assessments are performed by trained personnel at KEMA Labs.
For more information about type testing and certification needs of energy meters, please contact email@example.com.