Meter
Electric energy meter is a meter used to measure electrical energy, also known as watt-hour meter, fire meter, kilowatt-hour meter, and refers to a meter that measures various electrical quantities.
When using the electric energy meter, pay attention to that in the case of low voltage (not more than 500 volts) and small current (tens of amperes), the electric energy meter can be directly connected to the circuit for measurement. In the case of high voltage or high current, the electric energy meter cannot be directly connected to the line, and must be used with a voltage transformer or a current transformer.
Influencing factors of electric energy meter turning
1. Current direction
only changes the direction of the current, the induction reactive energy meter will reverse. In practice, due to the existence of reactive power over-compensation by customers or customers, the current passing through the reactive power meter may be reversed, and the reactive power meter turntable will reverse.
2, load properties
only change the nature of the customer's load, the reactive power meter turntable will reverse. The circuit load is divided into three categories: inductive, capacitive and resistive. Since the power reflected by the reactive energy meter is Q=UIsinφ, if the load is pure resistance, Q=0, the turntable will not rotate; if the load is inductive, Q》 0, the turntable rotates forward; if the load is capacitive, Q<0, the turntable reverses.
3, phase sequence
only changes the voltage phase sequence, and the reactive power meter turntable will reverse.
Since the electric energy meter is generally calibrated under the condition of forward rotation, when the electric energy meter is reversed, the direction of many compensation torques (such as light load compensation torque) will not change accordingly, so measurement errors will occur.
Reactive power meter dial may be, which makes it difficult for customers to measure reactive power. DL/T448-2000 stipulates that customers who implement the two-part electricity price system need to install an induction type active energy meter and a reactive energy meter with a non-reverse device due to the power factor assessment. When the power supply and the receiving party need to measure, that is, when the current direction is variable, two induction type active energy meters and reactive energy meters with non-reverse devices should be installed respectively.