What Is The Main Reason For The Wrong Wiring Of The Electric Energy Meter?
Dec 11, 2021| The main manifestations of the wrong wiring of the electric energy meter are: the electric energy meter reverses, does not rotate, and the speed becomes slow. Since the electric energy meter measuring device is composed of various components such as electric energy meter, mutual inductor, secondary circuit, etc., the error measurement and correction of electric energy meter also show diversified changes.
In order to measure electric energy in a fair, just, and reasonable manner, timely, fast, and correct diagnosis of wrong wiring and taking effective preventive measures are important topics for employees of power supply companies, and are effective ways to improve the image of power supply companies and reduce power loss.
1. Common wrong wiring of electric energy metering device
1. Wrong wiring of single-phase active energy meter
When the direct-connected single-phase electric energy meter is installed, the live wire and the neutral wire of the input electric energy meter are mistakenly connected. The neutral wire is in a disconnected state after being led out from the electric energy meter, and the load is connected across the live wire and the ground wire. , The electricity consumption is still normal, because the current coil of the electric energy meter does not turn because there is no current through it.
When the voltage hook is disconnected or poor contact causes an open circuit, the measured power of the electric energy meter P=U(0)×Icosφ=0, and the electric energy meter does not rotate. When the current transformer measures an open circuit for the second time, no current flows through the current coil of the electric energy meter, and the measured power of the electric energy meter is P=U(0)×Icosφ=0, and the electric energy meter does not rotate. Similarly, when the secondary side of the current transformer is short-circuited, the electric energy meter will not turn because there is no current flowing through the current coil. When the polarity of the secondary side of the current transformer is reversed, the power measured by the electric energy meter is P=-UIcosφ, and the electric energy meter is reversed.
2. Wrong wiring of three-phase three-wire two-element watt-hour meter
When the voltage line A and B phase voltage are reversed; B and C phase voltage are reversed; A and C phase voltage are reversed, the measured value P after the exchange is zero, and the energy meter does not rotate.
3. Wrong wiring of three-element watt-hour meter
When any current wire or TA polarity is connected reversely, the active power measured by reverse phase connection is negative, and the electric energy meter slows down.
When there is a two-phase current line or TA polarity is reversed, the measured value of the reversed two-phase is negative, and the energy meter is reversed.
When the three-phase current line or TA polarity is reversed, the electric energy meter is reversed, K=-1.
When one phase of the current loop is open, the electric energy meter only measures two-phase electricity; when two-phase is open, only one-phase electricity is measured; when three-phase is open, the electric energy meter stops. Similarly, when a one-phase, two-phase, or three-phase short circuit occurs in the current loop, the measurement value of the electric energy meter is the same as the above.
When the TA wiring of the low-voltage three-phase four-wire electric energy meter is correct, but the phase sequence of the voltage auxiliary line is inconsistent with the current, such as the electric energy meter reverses.
When the voltage circuit has an open circuit fault, it has the following characteristics: the one-phase voltage circuit is open, and the electric energy meter measures the two-phase electric quantity; when the two-phase voltage circuit is open, the electric energy meter only measures one-phase electric energy, and the electric energy meter slows down; and the three-phase voltage circuit is open. When the power meter stopped.