A kind of zero-sequence current method of calibrationTechnical field
The invention belongs to technical field of relay protection, in particular to a kind of zero-sequence current method of calibration.
Background technique
Currently, circuit relay protection device needs to acquire external zero-sequence current in relay protection system.But normallyElectric system does not have zero-sequence current when operation, thus can not directly judge whether external zero-sequence current circuit is normal.If externalZero-sequence current circuit is abnormal, and ground fault once occurs for electric system at this time, and protective relaying device will be unable to measurement zero-sequence current,It may cause relay fail, be current urgent problem.
Summary of the invention
The purpose of the present invention is to provide a kind of zero-sequence current method of calibration, can effectively identify external zero sequence electricityRoad is flowed back to the presence or absence of exception, the reliability of external zero-sequence current sampling is improved, improves safe effect.
In order to achieve the above objectives, solution of the invention is:
A kind of zero-sequence current method of calibration, includes the following steps:
Step 1, the action report of real-time detection line protective devices judges whether to start, detects route protectionDevice starting, reads the recorded wave file at corresponding moment, and executes step 2；
Step 2, the sampled data of route phase current and zero-sequence current is extracted from recorded wave file, and executes step 3；
Step 3, the sampled data of the phase current extracted according to step 2 calculates self-produced zero-sequence current amplitude and phase, according toThe zero-sequence current sampled data that step 2 is extracted calculates external zero-sequence current amplitude and phase, and executes step 4；
Step 4, the amplitude of comparison step 3 calculated self-produced zero-sequence current and external zero-sequence current, comparison step 3 calculateThe phase of self-produced zero-sequence current and external zero-sequence current out, and execute step 5；
Step 5, it is judged according to the comparison result of step 4, proposes that maintenance is suggested.
In above-mentioned steps 1, " starting " keyword in hunting action message records the corresponding message moment, then after findingContain the wave file at this moment in search file name in wave file list.
In above-mentioned steps 3, the amplitude of more self-produced zero-sequence current and external zero-sequence current, when the two phase absolute value of the difference is bigWhen first compares threshold value, it is determined as that amplitude is inconsistent；The phase of more self-produced zero-sequence current and external zero-sequence current, works as the twoWhen phase absolute value of the difference compares threshold value greater than second, it is determined as that phase is inconsistent.
Above-mentioned first range for comparing threshold value is 1-5% times of route rated current, and described second compares the range of threshold valueFor 1-10 degree.
The particular content of above-mentioned steps 4 is: if the amplitude of self-produced zero-sequence current and external zero-sequence current, phase all phasesTogether, it is determined as that current loop is normal；If any difference of the amplitude of self-produced zero-sequence current and external zero-sequence current, phase, is judged toCurrent loop is abnormal, it is proposed that checks external zero-sequence current circuit.
After adopting the above scheme, compared with prior art, the present invention external zero-sequence current circuit can effectively be identifiedWith the presence or absence of exception, the reliability of external zero-sequence current sampling is improved, safe effect is improved, has a good application prospect.
Detailed description of the invention
Fig. 1 is flow chart of the invention.
Specific embodiment
Below with reference to attached drawing, technical solution of the present invention and beneficial effect are described in detail.
The present invention provides a kind of zero-sequence current method of calibration, as shown in Figure 1, comprising the following steps:
Step (A), the action report of real-time detection line protective devices judge whether to start, and detect that route is protectedProtection unit starting, reads the recorded wave file at corresponding moment, and executes step (B)；If detecting, line protective devices are inactive,It repeats step (A), starts to verify next time；
In step (A), " starting " keyword in hunting action message records the corresponding message moment, then after findingContain the wave file at this moment in search file name in wave file list；
Step (B), extracts the sampled data of route phase current and zero-sequence current from recorded wave file, and executes step(C)；
Step (C) calculates self-produced zero-sequence current amplitude and phase according to the sampled data of step (B) phase current extracted,External zero-sequence current amplitude and phase are calculated according to the zero-sequence current sampled data that step (B) is extracted, and executes step (D)；
Step (D), the amplitude of comparison step (C) calculated self-produced zero-sequence current and external zero-sequence current, comparison step(C) phase of calculated self-produced zero-sequence current and external zero-sequence current, and execute step (E)；
In the step (D), the amplitude and phase of more self-produced zero-sequence current and external zero-sequence current, process is as follows:
(D1) amplitude of more self-produced zero-sequence current and external zero-sequence current, when the two phase absolute value of the difference is greater than the first ratioWhen compared with threshold value, it is determined as that amplitude is inconsistent, the described first range for comparing threshold value is 1-5% times of route rated current；
(D2) phase of more self-produced zero-sequence current and external zero-sequence current, when the two phase absolute value of the difference is greater than the second ratioWhen compared with threshold value, it is determined as that phase is inconsistent, the described second range for comparing threshold value is 1-10 degree；
Step (E) is judged according to the comparison result of step (D), proposes that maintenance suggests that steps are as follows:
(E1) if the amplitude of self-produced zero-sequence current and external zero-sequence current, phase are all identical, it is determined as current loop justOften；
(E2) if any difference of the amplitude of self-produced zero-sequence current and external zero-sequence current, phase, it is different to be judged to current loopOften, it is proposed that check external zero-sequence current circuit.
The above examples only illustrate the technical idea of the present invention, and this does not limit the scope of protection of the present invention, allAccording to the technical idea provided by the invention, any changes made on the basis of the technical scheme each falls within the scope of the present inventionWithin.