Transformer iron core and clamp member current standard exceeding alarm instrument

Abstract

The invention discloses a transformer iron core and clamp member current standard exceeding alarm instrument comprising two sensors, a conductive wire, a conditioning circuit, a transmission wire, a control box, a display screen, an MCU, an alarm device, a converter, a power supply and a battery. The external side of one of the sensors is sleeved by the conductive wire, and the other sensor is arranged at one side of the conductive wire. The two sensors are connected on the conditioning circuit. The conditioning circuit is connected on the control box via the transmission wire with a shielding layer. The display screen, the MCU, the alarm device, the converter, the power supply and the battery are installed in the control box. The MCU is respectively connected with the display screen, the alarm device, the converter and the power supply. When milliampere-level micro alternating current is measured by the device under the environment of strong electromagnetic interference, the instrument does not need to be close to the measured conductive wire through manual operation, influence generated by electromagnetic interference in the environment is eliminated from the measurement result, current can be automatically and continuously measured in real time and displayed after installation, and the instrument has an automatic alarm function when current exceeds the set value.

Description

technical field [0001] The invention relates to the field of measuring devices for alternating current, in particular to an automatic, accurate and real-time measuring device for alternating current in a transformer core and a clamp without disconnecting a conductor under test in a strong electromagnetic interference environment. device with alarm function. Background technique [0002] Using a clamp-type ammeter can measure the AC current flowing in the wire without disconnecting the wire. For the case where the current in the wire is very small (the current is at the milliamp level), there is a corresponding high-precision clamp-type leakage ammeter. In the interference environment, the electromagnetic interference in the environment will generate interference value in the current transformer of the clamp-type leakage ammeter. Since the AC current to be measured is very small, the interference value cannot be ignored, which will cause a large error in the measurement value...

AI Technical Summary

Problems solved by technology

[0002] Using a clamp ammeter can measure the AC current flowing in the wire without disconnecting the wire. For the case where the current in the wire is very small (the current is at the milliampere level), there is a corresponding high-precision clamp leakage ammeter. In the interference environment, the electromagnetic interference in the environment will generate interference values ​​in the current transformer of the clamp leakage ammeter. Since the AC current to be measured is small, the interference value cannot be ignored, which will cause a large error to the measured value. It truly reflects the actual value of the current in the wire. For example, it is the case to measure the leakage current of the transformer iron core and the clamp in the substation. The method currently used to eliminate the interference value is: first use the clamp leakage current meter to cover the wire to read Get a reading that is the initial measurement value, then move the clamp leakage current meter to the side of the wire, close it without covering the wire and read a reading that is the interference value, and then calculate the result obtained by subtracting the interference value from the initial measurement value as The actual value of the current in the wire, this measurement has the following disadvantages: First, it requires personnel to hold the meter close to the wire to be tested, which shortens the distance from the live equipment, which is dangerous to the person; second, when there are many devices around the wire and the When the channels left for personnel are limited, it is difficult for measuring personnel to approach the wires; thirdly, two readings and calculations are required, and there is a time delay. When the current in the wires changes, the actual value of the current cannot be continuously reflected in real time

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