Online monitoring device and monitoring method of multipoint earthing of iron core of transformer

Abstract

The invention provides an online monitoring device and a monitoring method of multipoint earthing of an iron core of a transformer. The device comprises a current transformer, an ammeter and an adjustable resistor, which are installed in a housing. The ammeter is series-connected on the secondary side of the current transformer. The ammeter range has double-layer scales. The adjustable resistor isseries-connected on the secondary side of the ammeter. The device is series-connected in an earthing wire of the iron core and the housing of the device is singly earthed. When the iron core is earthed in multipoint, the adjustable resistor is adjusted according to the earthing current, the current flowing through the iron core is controlled and the indicated number on the ammeter is observed toenable the current to reach the value displayed when the transformer runs normally. The invention has the effects of enjoying simple structure, convenient installation, simple method and accurate andreliable monitoring, being capable of timely and accurately monitoring the running state of the iron core of the transformer in real time, achieving the aim of protecting the transformer and manufacturing the device into integrated structure so that the device is both practical and beautiful.

Description

technical field [0001] The invention relates to a device and a monitoring method for on-line monitoring when the iron core of a large-scale power transformer is grounded at multiple points. Background technique [0002] In the power system, the main transformer is the most important equipment in the substation (station), and it is also the equipment that is easy to cause accidents. Once the main transformer fails, the substation (station) will be forced to shut down, which will directly affect the safe and reliable operation of the power system and cause great economic losses. Among the many types of transformer faults, multi-point grounding of iron core is a common fault. Therefore, it is very important to accurately diagnose and deal with multi-point grounding faults of main transformer iron core and eliminate them in the bud. [0003] The basic form of the main transformer core grounding is: the silicon steel sheets are stacked together to form an iron core, and each sil...

AI Technical Summary

Problems solved by technology

The disadvantages of this method are: 1) The multi-point grounding fault of the iron core can occur at any time, once it occurs, it cannot be found in time

2), sometimes the multi-point grounding point of the iron core is intermittent (within a period of time) or intermittent, and no monitoring is carried out when the grounding occurs, and it cannot be detected when the grounding point is disconnected

3) When using a card meter to measure the grounding current of the iron core, it belongs to live work. The staff must hold a live work certificate and apply for a work ticket for live work. The working procedures are relatively complicated.

4) When measuring the ground current with a card meter, the measured data is inaccurate due to the magnetic flux leakage around the running transformer

5) After the iron core is found to be grounded at multiple points, it needs to be dealt with by a power outage hanging cover, which generally takes 7 working days

It is not conducive to safe and reliable power supply, reduces economic benefits, and at the same time takes labor and time

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