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Three wiring methods of generator three-phase power meter
May 17, 2022
Three-phase power meters are used to measure the output power of three-phase generators, generally with power converters. The precautions of the instrument, including the selection of the accuracy of the electrical measuring instrument, the selection of the range of the electrical measuring instrument, etc., and the connection method of the three-phase power meter for you.
1. Precautions for the selection of electrical measuring instruments
1.1 Selection of the accuracy of electrical measuring instruments
In order to ensure the accuracy of the measurement, it is better to choose the instrument with higher accuracy, but because the surface of the instrument used for the 100KW generator control box is small and the use conditions are poor. Therefore, the instrument with higher accuracy is generally not used. GB10234- 88 General technical requirements for control panels for AC mobile power stations.
The accuracy level of the monitoring frequency meter should not be lower than 5.0, and the accuracy level of other monitoring instruments should not be lower than 2.5.
1.2 Selection of the range of electrical measuring instruments
The selection of the range of the electrical measuring instrument should be such that when the generator is running at the rated power, the pointer of the instrument indicates about 2/3 of the scale. If the pointer indication is lower than this scale, it means that the range selection of the instrument is too large, and the error of the instrument increases; if the pointer indication is higher than this scale, it means that the range selection of the instrument is too small, the measurement margin is small, and sometimes it cannot meet the operating requirements of the unit.
2. The connection method of the three-phase power meter
2.1 The three-phase voltage and current connected to the three-phase power meter are directly connected to the power converter without the transformer, and the three-phase power is converted by the converter and then connected to the power meter for reading. This connection method is usually used to measure small power with voltage 400V and current below 5A.
2.2 The three-phase voltage connected to the three-phase power meter is directly connected to the power converter without the voltage transformer, but the current side is connected to the power converter through the current transformer. This connection method is usually used to measure the high power of 400V current above 5A.
2.3 The three-phase voltage and current connected to the three-phase power meter pass through the transformer, and then connect to the power converter. This connection can measure the power under any voltage and current as long as it is equipped with voltage and current transformers with different transformation ratios.
The above three wiring methods are also applicable to the three-phase power meter without power converter. In this case, it is only necessary to change the wiring connected to each terminal of the converter to the corresponding terminal of the three-phase power meter.
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