First, use a multimeter to measure the voltage value of the input auxiliary power supply. The normal voltage range of the multi-function meter is AC/DC85-265V. You need to confirm it according to the site conditions. If the voltage value exceeds the auxiliary power supply, the meter may be damaged or even burned. If the auxiliary power supply is normal, check whether the auxiliary power supply wiring of the multi-function power meter is properly connected. If the auxiliary power supply is normal and the wiring is in place, the meter has no display. After power off, power on again. If the meter still cannot display normally, please contact the meter manufacturer.
If the measurement of the multi-function electric energy meter is abnormal, the electric energy meter may be damaged on the one hand, and the fault may be caused by the poor wiring of the instrument or the transformer on the other hand. So how to judge and exclude it?
When the active power P value of the multi-function power meter is negative, and the measurement of electric energy, power and power factor is wrong, it can be eliminated according to the following two methods.
Method 1: Determine whether the wiring of the multi-function instrument terminal is faulty
Under normal circumstances, the phase sequence of the intelligent multi-function power meter is: Ua-Ia; Ub-Ib; Uc-Ic.If the power is negative and the power factor and electric energy measurement are wrong, first check that the phase sequence of the terminals of the multi-function power meter is normal. If the phase sequence is normal, but the meter data is abnormal, please check whether the incoming and outgoing wires of the secondary side of the current transformer are connected correctly.
Method 2: Judge whether the wiring of the incoming and outgoing wires of the secondary side current transformer is faulty
If the active power P value of the multi-function power meter is negative, and the measurement of electric energy, power and power factor is wrong, we first rule out whether it is a wiring fault in the incoming line of the power meter. If the wiring of the incoming terminal of the instrument is normal, we will check whether the wiring of the secondary side current transformer is normal. Under normal circumstances, the connection method of the incoming and outgoing wires of the current transformer: Ia* incoming wire, Ia outgoing wire; Ib* incoming wire, Ib outgoing wire; Ic* incoming wire, Ic outgoing wire.
If the wiring of the secondary side of the current transformer is faulty, the following phenomena will occur:
(1) Active power is negative
(2) Abnormal energy metering
(3) Abnormal power factor
If the above two fault causes are eliminated, but the instrument still has the above fault phenomenon, please contact the instrument manufacturer.
First, check the cause of the inaccurate display of voltage and current, whether the current or voltage magnification set by the instrument is inconsistent with the actual transformer magnification used in the periphery. If it is inconsistent, the user can change the setting according to the actual situation on site. Eliminate the above reasons, carefully check whether the voltage or current wiring is interchangeable or reversed, and then use a multimeter to measure the voltage and current signals to confirm that the normal voltage and current signals are connected.
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