A method for detecting ground fault of high voltage power equipment based on spectrum analysis

Abstract

The present invention provides a method for detecting grounding faults of high-voltage electric equipment based on spectrum analysis, comprising: (1): collecting grounding current signals of high-voltage electric equipment; (2): calculating the amplitude of the current signal; (3): judging whether the amplitude of the current signal is greater than a reference value, if so, the current signal is the first pulse starting point, and entering (4); if not, returning to (1); (4): judging the polarity of the current signal; (5): making a preliminary judgment based on the polarity of the current signal; (6): extracting the current signal before and after the first pulse starting point; (7): calculating the spectrum integral of the high-frequency component of the current signal; (8): calculating the spectrum integral difference of the high-frequency component of the current signal before and after the first pulse starting point; (9): judging whether a grounding fault occurs in the electric equipment. The present invention provides a method for detecting grounding faults of high-voltage electric equipment based on spectrum analysis, which can accurately detect grounding faults of high-voltage electric equipment.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric power detection, and in particular relates to a ground fault detection method for high-voltage electric power equipment based on spectrum analysis. Background Art

[0002] As an important part of the power system, the safe and reliable operation of high-voltage power equipment is an important guarantee for the safety and reliability of the power transmission and distribution system and power users. Ground fault is a common fault in the power transmission and distribution system, and the ground fault detection of high-voltage power equipment is mainly judged based on the magnitude of the ground current. Sometimes, misjudgment may occur, which leads to unnecessary losses.

[0003] The present invention proposes a method for detecting ground faults in high-voltage power equipment based on spectrum analysis, which makes a preliminary judgment based on the extreme value of the ground current signal, and then The frequency spectrum integral difference of the high-frequency component of the current signal is used to determine whether a ground fault occurs in the high-voltage power equipment, thereby improving the accuracy of the detection result. Summary of the invention

[0004] The present invention provides a method for detecting grounding faults of high-voltage electric equipment based on spectrum analysis, which can accurately detect grounding faults of high-voltage electric equipment.

[0005] The present invention is specifically a method for detecting grounding faults of high-voltage electric equipment based on spectrum analysis, and the method for detecting grounding faults of high-voltage electric equipment comprises the following steps:

[0006] Step (1): collecting the ground current signal of the high-voltage power equipment;

[0007] Step (2): calculating the amplitude of the current signal;

[0008] Step (3): determine whether the amplitude of the current signal is greater than a reference value. If so, the current signal is the first pulse starting point, and proceed to step (4); if not, return to step (1);

[0009] Step (4): determining the polarity of the current signal and recording it;

[0010] Step (5): making a preliminary judgment based on the polarity of the current signal;

[0011] Step (6): Extract the first pulse starting point The current signal, after the first pulse starting point The current signal;

[0012] Step (7): Calculating the frequency spectrum integral of the high frequency component of the current signal;

[0013] Step (8): Calculate the time before the first pulse starting point The spectrum integral of the high frequency component of the current signal and the first pulse starting point after The frequency spectrum integral difference of the high frequency component of the current signal;

[0014] Step (9): Determine whether a ground fault occurs in the power equipment and display an alarm in a timely manner.

[0015] The specific method for making a preliminary judgment based on the polarity of the current signal in step (5) is: if the polarity is negative, the high-voltage power equipment has no grounding fault; if the polarity is positive, further analysis and judgment is performed.

[0016] The specific method for calculating the spectrum integral of the high-frequency component of the current signal in step (7) is:

[0017] First, the current signal is Fourier transformed Wherein i(t) is the current signal;

[0018] Secondly, the spectrum integral of the high frequency component of the current signal is calculated: f0=1kHz, f1=100kHz.

[0019] The specific method for determining whether a ground fault occurs in the power equipment in step (8) is as follows: comparing the spectrum integral difference with a difference reference value; if the spectrum integral difference is greater than the difference reference value, a ground fault occurs in the high-voltage power equipment; if the spectrum integral difference is less than the difference reference value, a ground fault does not occur in the high-voltage power equipment.

[0020] The continuous time during which the amplitude of the current signal is greater than the reference value is counted, and the continuous time is analyzed. If it is greater than the continuous time reference value, an alarm is issued in time.

[0021] Compared with the prior art, the beneficial effect is that the method for detecting ground fault of high-voltage power equipment based on spectrum analysis makes a preliminary judgment based on the extreme value of the ground current signal, and then The frequency spectrum integral difference of the high-frequency component of the current signal is used to determine whether a ground fault occurs in the high-voltage power equipment, thereby improving the accuracy of the detection result. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The present invention is a flowchart of a method for detecting grounding faults of high-voltage electric equipment based on spectrum analysis. DETAILED DESCRIPTION

[0023] The specific implementation of a method for detecting grounding faults of high-voltage electric power equipment based on spectrum analysis of the present invention is described in detail below in conjunction with the accompanying drawings.

[0024] like Figure 1 As shown, the method for detecting grounding faults of high-voltage electric equipment based on spectrum analysis of the present invention comprises the following steps:

[0025] Step (1): collecting the ground current signal of the high-voltage power equipment;

[0026] Step (2): calculating the amplitude of the current signal;

[0027] Step (3): determine whether the amplitude of the current signal is greater than a reference value. If so, the current signal is the first pulse starting point, and proceed to step (4); if not, return to step (1);

[0028] Step (4): determining the polarity of the current signal and recording it;

[0029] Step (5): Perform a preliminary judgment based on the polarity of the current signal: if the polarity is negative, the high-voltage power equipment does not have a ground fault, and return to step (1); if the polarity is positive, proceed to step (6) for further analysis and judgment;

[0030] Step (6): Extract the first pulse starting point The current signal, after the first pulse starting point The current signal;

[0031] Step (7): Calculate the frequency spectrum integral of the high frequency component of the current signal: First, perform Fourier transform on the current signal Where i(t) is the current signal; secondly, the spectrum integral of the high-frequency component of the current signal is calculated: f0=1kHz, f1=100kHz;

[0032] Step (8): Calculate the time before the first pulse starting point The spectrum integral of the high frequency component of the current signal and the first pulse starting point after The frequency spectrum integral difference of the high frequency component of the current signal;

[0033] Step (9): Determine whether a ground fault occurs in the electric power equipment: compare the spectrum integral difference with a difference reference value; if the spectrum integral difference is greater than the difference reference value, a ground fault occurs in the high-voltage electric power equipment, and an alarm is displayed in time; if the spectrum integral difference is less than the difference reference value, a ground fault does not occur in the high-voltage electric power equipment.

[0034] The continuous time during which the amplitude of the current signal is greater than the reference value is counted, and the continuous time is analyzed. If it is greater than the continuous time reference value, an alarm is issued in time.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and are not intended to limit the present invention. A person skilled in the art should understand that the specific implementation of the present invention can be modified or replaced by equivalents, but these modifications or changes are within the scope of protection of the pending claims.

Claims

1. A method for detecting ground faults in high-voltage power equipment based on spectrum analysis, characterized in that: The method for detecting ground fault of high voltage electric equipment comprises the following steps: Step (1): collecting the ground current signal of the high-voltage power equipment; Step (2): calculating the amplitude of the current signal; Step (3): determine whether the amplitude of the current signal is greater than a reference value. If so, the current signal is the first pulse starting point, and proceed to step (4); if not, return to step (1); Step (4): determining the polarity of the current signal and recording it; Step (5): performing a preliminary judgment based on the polarity of the current signal; the specific method of performing a preliminary judgment based on the polarity of the current signal is: if the polarity is negative, the high-voltage power equipment does not have a ground fault; if the polarity is positive, further analysis and judgment are performed; Step (6): Extract the first pulse starting point The current signal, after the first pulse starting point The current signal; Step (7): Calculating the frequency spectrum integral of the high frequency component of the current signal; Step (8): Calculate the time before the first pulse starting point The spectrum integral of the high frequency component of the current signal and the first pulse starting point after The frequency spectrum integral difference of the high frequency component of the current signal; Step (9): Determine whether a ground fault occurs in the power equipment, and display an alarm in time; the specific method for determining whether a ground fault occurs in the power equipment is: compare the spectrum integral difference with the difference reference value; if it is greater than the difference reference value, a ground fault occurs in the high-voltage power equipment; if it is not greater than the difference reference value, a ground fault does not occur in the high-voltage power equipment.

2. A method for detecting ground faults of high-voltage power equipment based on spectrum analysis according to claim 1, characterized in that: The specific method for calculating the spectrum integral of the high-frequency component of the current signal in step (7) is: First, the current signal is Fourier transformed Wherein i(t) is the current signal; Secondly, the spectrum integral of the high frequency component of the current signal is calculated: f0=1kHz, f1=100kHz.

3. A method for detecting ground faults of high-voltage power equipment based on spectrum analysis according to claim 2, characterized in that: The continuous time during which the amplitude of the current signal is greater than the reference value is counted, and the continuous time is analyzed. If it is greater than the continuous time reference value, an alarm is issued in time.

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