There are three transformer type fault recording devices connected to a substation in Inner Mongolia, but the fault recording devices are frequently started recently, which has caused great trouble to operators and seriously affected their judgment and safety awareness.

The frequent start of fault recorder is mostly caused by the impact load and bus voltage fluctuation of substation. The frequent start of fault recorder reduces the speed of fault analysis and processing. At the same time, the large amount of data in substation also affects the safe and stable operation of fault recorder.

Firstly, the operation of the fault recording device is investigated. Firstly, the actual implementation of the setting value of the fault recording device is checked to make sure that it is consistent with the setting value notice issued by the regional dispatching. It is found that the actual load impact and voltage fluctuation of the system are greater than the starting value of the fault recorder.

According to the input signals of current, voltage and switching value collected by the fault recorder on site, analyze and judge various starting conditions of fault recorder, such as sudden variable current, sudden variable voltage, zero sequence current and negative sequence current, determine whether the input signal meets the requirements of starting fault recorder, and then decide whether to start fault recorder.

Fault recorder starts fault recorder frequently in case of load disturbance or voltage fluctuation, because there is a starting condition of sudden variable in fault recorder. Fault recorder starts fault recorder in a short time when sudden variable exceeds the standard, which causes fault recorder to start frequently. Therefore, we need to find a method, not only to judge whether the sudden variable exceeds the standard, but also to judge the duration of the sudden variable exceeding the standard. Only when the sudden variable exceeds the standard and the duration exceeds a certain time, can we start the fault recording function, and form the fault recording file and fault recording report. The concept of inverse time over-current protection is proposed, which can effectively solve the problem of frequent start-up of fault recorder without reducing the sensitivity of fault recorder.

When a fault occurs, the protection device generally has a trip signal output, which can be connected to the protection trip switch signal of the fault recording device to determine whether it is necessary to start the fault recording function.

Therefore, it is necessary to solve the problem of frequent start-up and frequent alarm signal of fault recorder when load disturbance or voltage fluctuation occurs. In order to solve the problem of frequent start-up of fault recorder, it is necessary to greatly reduce the number of start-up recorder files and start-up reports which have little significance for fault analysis, and improve the efficiency of obtaining fault recorder files and fault recorder reports. To ensure that the fault recording device can operate reliably and record correctly in case of system fault, provide technical support for rapid analysis and treatment of fault, create conditions for rapid recovery of power supply, so as to improve the power supply reliability of power grid and protect the safe and stable operation of the whole power grid.