How to Use Leakage Current Clamp Meter to Check for Line Leakage or Stealing
If you suspect line leakage or tampering, the use of leakage current clamp meter power down the test will help assess the integrity of the insulation of the circuit and help determine if a problem exists and where there is a problem.
Beijing Jintai Scientific Instrument Co., Ltd. specializes in leakage current clamp meter
1 Judging whether the residual current operation protector itself has a problem Leakage current clamp meter If the residual current operation protector is not put into operation or frequently protected: At the distribution transformer, use a leakage current clamp meter to clamp the AC contactor or open circuit leakage. an outlet three-phase line and a neutral line side, the residual current operated protective device forcibly put into operation, is displayed if the value of the leakage current is greater than 300mA clamp meter, it proves residual current protection is good, then the application Leakage current clamp meter to determine which phase is leakage; otherwise, should repair or replace the residual current protection device.
2 Which phase is the phase leakage leakage current clamp meter?
In the distribution transformer, the AC contactor will control the low voltage line side of the neutral line is disconnected, and the fuse has been removed after the die is mounted on a phase wherein the measured phase with the leakage current clamp tableau The measured value is the leakage current value of the phase. According to the same method, the leakage current values ​​of the remaining phases are measured in sequence.
In order to prevent the line grounding on the line (such as the use of one-line method to steal electricity, etc.), a large current damages the meter. First, the leakage current clamp meter position is placed on the maximum range ; if the display value is small, then The leakage current clamp meter range was converted to milliamperes.
3 After determining the phase line with leakage current, determine the position of leakage current Leakage current clamp meter
At the distribution transformer, the phase conductor to be inspected is plugged into the fuse core, and the neutral line and the remaining two phases of the fuses are all disconnected. The energized phase line is used to measure the leakage current position by using a leakage current clamp meter . In order to improve efficiency, the position of the pole can be selected in the middle of the line, and it can be determined through detection whether the leakage part is in the first half or the second half of the line, and then goes to the line segment where the leakage is suspected . And so on, to narrow the detection range. Finally, the phase post insulator in a relatively small range is detected, and the phase line of the user access line connected to the phase line in the range is detected (can be performed on the ground, or when the insulator is detected At the same time) to determine the specific part of the leakage.
In the case of power transmission on a low-voltage line, it is also possible to detect a leakage current clamp meter for a low-voltage user access line within a suspected range. During the test, the phase and neutral wires of the single-phase user should be placed in the jaws of the leakage current clamp meter at the same time; the three phase wires and the neutral wire of the three-phase user should also be put into the jaws at the same time. If there is no leakage fault, then the phasor of the load current flux is zero, and the display value of the leakage current clamp meter is also zero; if there is a leakage current, the magnitude of the leakage current can be detected.
4 Check the user's internal wiring and equipment for leakage current leakage clamp meter
A leakage current clamp meter is used to measure the leakage current value at the user's power input line, and the user's power equipment and lamps are input and withdrawn one by one. The leakage current is found by looking at the change in the leakage current value measured by the leakage current clamp meter. Equipment or lamps; if all the equipment and lamps are normal, or the devices that have leakage have been withdrawn, but the leakage current clamp meter shows that the user still has a leakage current, it may be that the user's low-voltage line leakage. It should be handled as the case may be. For the leakage failure of buried buried pipelines, only line changing or rewiring processing methods can be adopted .
5 Problems to Note Leakage Current Clamp Meter
5.1 In the search for leakage faults, the AC contactor controlling the low voltage line needs to forcibly send power for a short time.
5.2 When looking for leakage faults, pay attention to safety. Someone must monitor and take safety measures. When reading the leakage current clamp meter data, be sure to maintain the safe distance between the human body and the live parts . It is best to use the HOLD (Data Hold) function on the Leakage Current Clamp Meter.
5.3 Higher harmonics interfere with a small number of residual current operated protectors and may cause them to malfunction. If there are large harmonic source users such as mid-frequency furnaces in the station area, such users should be temporarily withdrawn from the operation when testing .
5.4 The use of a leakage current clamp meter is particularly effective for the search for "line-by-line" power-saving households. Its characteristic is that the leakage current clamp meter shows a large value, reaching several hundred milliamps or even several amps. For the unknown burglarizers, the above method can be used to find out. If there is such suspicion of stealing power, it can be directly checked at the connection line with a leakage current clamp meter.
5.5 The above examples are only used as a reference to explain the role of the leakage current clamp meter in practical use.
Beijing Jintai Keyi Testing Instrument Co., Ltd. is a company specializing in the production and distribution of domestic and foreign instrumentation companies, able to complete instrumentation engineering product support and maintenance services, services in electronics, electricity, communications, environmental protection, agriculture, construction, energy saving, aerospace And other industries; over the years, the company "as real service, low prices" as its purpose, for the majority of users at home and abroad to provide a thoughtful pre-sale, sales, after-sales service.
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