1. Wrong wiring of single-phase active energy meter When the direct-connected single-phase electric energy meter is loaded, the live line of the electric energy meter is reversed and the zero line is reversed. The zero line is in the breaking state after being led out from the electric energy meter. The load is connected between the live line and the ground line. As shown in Figure 1, the power consumption is still normal, because the current meter current coil has no current and does not turn.
When the voltage small hook is disconnected or the contact is poor, the wiring is as shown in Fig. 2. At this time, the measured power of the electric energy meter P=(0)×IcosΦ=0, the electric energy meter does not rotate.
When the current transformer detects the open circuit twice, the current meter current coil has no current, and the power measured by the energy meter P=U(0)cosΦ=0, the electric energy meter does not rotate. Similarly, when the secondary side of the current transformer is short-circuited, the current 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 energy meter P'=-UIcosΦ energy meter is reversed, and the wiring is as shown in FIG.
2, three-phase three-wire two-element energy meter error wiring when the voltage line A, B phase voltage is reversed; B, C phase voltage is reversed; A, C phase voltage is adjusted, the adjusted measurement value P' is zero, the electric energy meter does not turn .
3. Wrong wiring of three-phase three-element energy meter When there is any current line or CT polarity is reversed, the active power of the reverse phase measurement is negative, and the correction coefficient of the energy meter becomes slow.
When there is a two-phase current line or the CT polarity is reversed, the measured value of the opposite phase is negative, and the correction coefficient is reversed.
When the three-phase current line or CT polarity is reversed, the energy meter is inverted, K=-1.
When the current loop is open in one phase, the energy meter only measures the two-phase power; when the two-phase is open, only one phase is measured; when the three-phase is open, the energy meter stops. Similarly, when one-phase, two-phase, and three-phase short-circuit occurs in the current loop, the metering value of the electric energy meter is the same as above.
When the CT wiring of the low-voltage three-phase four-wire electric energy meter is correct, and the phase sequence of the voltage auxiliary line is inconsistent with the current, for example, the electric energy meter is reversed.
When there is an open circuit fault in the voltage loop, 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 quantity, and the electric energy meter becomes slow; when the three-phase voltage circuit is open, the electric energy meter stops.
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