The difference between three-phase high-supply high meter and high-supply low meter
The three-phase high-supply meter refers to high-voltage power supply and high-voltage metering. Generally, the meter on the high-voltage side of the transformer measures the electricity through the transformer. High-supply and low-metering refers to high-voltage power supply and low-voltage metering. Generally, electricity is directly measured by an ammeter on the low-voltage side of the transformer. The advantages of the high-supply and high-meter metering method are to reduce the workload of metering management, meet the metering requirements to the greatest extent, and have great controllability; it can effectively prevent users from stealing electricity. However, this method also has some disadvantages. The following is the difference between the two tables for your reference:
(1) Cannot meet the requirements of electricity price classification. Due to the difference in electricity price due to the nature of electricity consumption and the type of electricity consumption, for the convenience of billing, different types of loads should be metered separately.
It is difficult to match the CT with the actual power load to meet the metering requirements (the primary current of the CT should meet 20%-10% of the rated current. The first is that there are several users connected to the T on the high-voltage line in rural areas, and the power consumption categories are different, plus the seasonal load in rural areas (Drought and flood control drainage and irrigation electricity), there is a big difference between peak and valley 24 hours a day, and the simultaneous rate of electricity consumption is very low. Second, in economically underdeveloped areas, non-continuous production enterprises have large day and night load fluctuations, and the electricity load is very unbalanced. Therefore, CT matching is difficult to meet the measurement requirements. If the CT magnification is large, it will inevitably cause the electric energy meter to stop or be distorted when the load is small (22:00~8:00); on the contrary, the CT magnification is small, and it is easy to burn out the CT , and also
affect measurement accuracy. Therefore, it is not appropriate to choose a metering method with high supply and high calculation for rural electricity consumption and industrial and mining enterprise users with discontinuous production.
There should be no difference between high supply and high calculation and high supply and low calculation, right?
There is a difference. The high-supply and high-meter electric energy metering device is installed on the high-voltage side of the receiving transformer, and the high-supply and low-meter electric energy metering device is installed on the low-voltage side of the receiving transformer. In addition to the copied power, the power of the high supply and low meter should also be added with the variable loss power.
2 How to choose the measurement method of high supply meter
(1) The measurement method of high supply and high meter is suitable for industrial and mining enterprises with three-shift production with little change in load, high load rate and balanced load. The selection of meters and transformers should meet the accuracy requirements.
(2) Do a good job in user load prediction, grasp the user's production nature, production process, power load and changes, and meet the best match between CT and load current.
(3) Test the secondary pressure drop of PT to meet the requirement that the secondary pressure drop of PT is not greater than the allowable value.
