How to Choose an Electronic Energy Meter
Compared with inductive energy meters, electronic energy meters have many advantages, such as high accuracy, low power consumption, small starting current, wide load range, and no mechanical wear, and are widely used. However, there are many manufacturers of electronic energy meters on the market, the quality levels are uneven, and the selection is not good. Not only can the advantages of electronic energy meters not be played, but it will bring undue losses and increase the workload of maintenance and management.
1. From the appearance model, the letter of the third digit of the electronic energy meter is S, for example, DDS is a single-phase electronic energy meter. DSS is a three-phase three-wire electronic energy meter, and DTS is a three-phase four-wire electronic energy meter.
2. Check the actual meter.
The inspection of the physical energy meter sent by the manufacturer is mainly prohibited from the following aspects. Namely: mechanical requirements, climatic conditions that can be adapted, electrical requirements, electromagnetic compatibility, and accuracy requirements:
a. Mechanical requirements:
Most of the mechanical requirements can be checked by visual inspection and simple test methods.
b. Accuracy requirements:
Accuracy requirements include. Current and red-yellow-blue factor changes, voltage changes, frequency changes, start-up tests, potential tests, and word-movement tests, etc., can be tested by general city-level and county-level power supply enterprises. Electronic energy meters generally have better linearity within the load range specified in the regulations. However, the actual accuracy of the load range of different manufacturers is very different. Since the actual load current on site changes frequently, the wider the load range that can be accurately measured, the better the load performance of the meter.
Accuracy requirements also include, such as harmonics, external magnetic induction, high frequency electromagnetic field effects, etc. You can ask the authoritative electric power laboratory to check.
c. Electrical requirements:
Power consumption inspection of electrical requirements, including voltage line and current line, can be used to measure the voltage, current and load impedance of the electric energy meter with a transformer calibrator, and then calculate the power consumption of the electric energy meter under the rated voltage and rated current.
d. Climatic conditions and electromagnetic compatibility performance:
Both of these are important for electronic energy. In particular, the electromagnetic compatibility performance has a very serious impact on the electronic energy meter. The meter with poor electromagnetic compatibility performance often appears "crash", "flying words" and other phenomena during on-site operation, and even the internal electronic components are damaged. This is an important feature that distinguishes electronic energy meters from mechanical energy meters. There are 5 items in the electromagnetic compatibility test, namely: electrostatic discharge test, high frequency electromagnetic field test, electrical fast transient burst test, surge test, and radio interference suppression test. Among them, the surge and pulse group are relatively close to some transient conditions in the power grid. It is recommended that the prefecture-level and county-level power supply enterprises with conditions purchase corresponding equipment and conduct spot checks on the electric energy meter.
