Early warning method for abnormal electric field in transformer substation

Abstract

The invention particularly relates to an early warning method for an abnormal electric field in a transformer substation, and belongs to the technical field of power equipment early warning. Two electric field acquisition points are arranged in the transformer substation, then voltage acquisition is performed on the two electric field acquisition points through voltage sensors with four layers of polar plates, and environmental electromagnetic interference between the voltage sensors and the transformer substation is eliminated by performing three-stage differential conditioning on the acquired four voltage data. Therefore, the voltage data collected by the voltage sensor is more accurate, and the early warning accuracy of the abnormal electric field in the transformer substation is improved. According to the method for comprehensively judging the abnormal electric field through the electric field intensity of the two points in the transformer substation, wrong early warning and missing early warning possibly brought by single-point early warning are eliminated, and the early warning accuracy of the abnormal electric field in the transformer substation is improved.

Description

Technical Field

[0001] The present invention specifically relates to an early warning method for abnormal electric field in a transformer substation, and belongs to the technical field of early warning of electric power equipment. Background Art

[0002] The substations of power grids with a voltage of 220 kV and below are unmanned, and the substations with a voltage of 500 kV and above are becoming less manned. This has put forward higher requirements for the operation and maintenance of equipment in substations. It is often necessary to enter the substation for regular maintenance or status maintenance of equipment. When carrying out maintenance work, the area near the power outage area is often energized. In order to ensure the personal safety of maintenance personnel, it is necessary to detect and warn the abnormal electric field in the substation to protect the maintenance personnel. The detection and warning of abnormal electric fields in existing substations mostly use electric field sensors to detect the electric field strength. If the detected electric field strength is higher than the threshold, an alarm is issued. Since the electromagnetic interference in the substation has a great influence on the accurate measurement of the electric field sensor, the detection accuracy of abnormal electric field strength in the substation is low, which is easy to cause safety accidents. Summary of the invention

[0003] The technical problem to be solved by the present invention is: how to accurately warn of abnormal electric fields in substations

[0004] In order to solve the above technical problems, the technical solution proposed by the present invention is: an early warning method for abnormal electric field in a substation, comprising the following steps:

[0005] Step 1: Two electric field collection points are set in the substation, namely the first electric field collection point and the second electric field collection point; the first voltage sensor and the second voltage sensor are respectively set at the first electric field collection point and the second electric field collection point; the first voltage sensor collects four voltage values ​​from the four layers of plates from top to bottom, namely The second voltage sensor collects four voltage values ​​from top to bottom by four layers of plates. ; Set the warning period T for abnormal electric field warning in the substation;

[0006] Step 2: Within one warning cycle T, the first voltage sensor and the second voltage sensor both collect data once, and collect the collected data to form a first voltage data set U1 and a second voltage data set U2, as shown in the following formula (1):

[0007] (1)

[0008] In formula (1), are four voltage values ​​collected by the first voltage sensor within the warning period T; are four voltage values ​​collected by the second voltage sensor within the warning period T;

[0009] Step 3: Substitute all the data in the first voltage data set U1 into the following formula (2) and perform triple differential conditioning to obtain the voltage of the first electric field collection point collected by the first voltage sensor within the warning period T: ,

[0010] (2)

[0011] In formula (2), are the first, second and third difference conditioning coefficients, all of which are empirical values;

[0012] According to the voltage of the first electric field collection point Calculate the first electric field strength of the first electric field collection point within the warning period T , as shown in the following formula (3),

[0013] (3)

[0014] In formula (3), is the dielectric constant of air; are the metal effective areas of the four plates of the first voltage sensor; R m11 is the sampling resistance value between the first electrode plate and the second electrode plate of the first voltage sensor; R m12 is the sampling resistance value between the third plate and the fourth plate of the first voltage sensor;

[0015] Step 4: Repeat the principle of step 3 to calculate the second electric field strength of the second electric field collection point within the warning period T ;

[0016] The first electric field strength and the second electric field strength Substitute it into the following formula (4) to make a judgment:

[0017] (4)

[0018] If formula (4) is satisfied, it means that there is an abnormal electric field in the substation, and an alarm is issued;

[0019] If formula (4) is not satisfied, proceed to step 5;

[0020] Step 5: Set the first electric field strength and the second electric field strength Substitute it into the following formula (5) to make a judgment:

[0021] (5)

[0022] If formula (5) is satisfied, it means that there is an abnormal electric field in the substation, and an alarm is issued;

[0023] If formula (5) is not satisfied, it means that there is no abnormality in the substation within the warning period T.

[0024] Beneficial effects of the present invention: 1. The present invention sets two electric field collection points in the substation, and then respectively collects voltage at the two electric field collection points through voltage sensors with four layers of plates, and eliminates the electromagnetic interference of the voltage sensor itself and the environment in the substation through three-level differential conditioning of the four collected voltage data, so that the voltage data collected by the voltage sensor is more accurate, and the early warning accuracy of abnormal electric fields in the substation is improved. 2. The present invention adopts a method of comprehensively judging abnormal electric fields based on the electric field strength at two points in the substation, which eliminates the false early warning and missed early warning that may be caused by single-point early warning, and increases the early warning accuracy of abnormal electric fields in the substation. DETAILED DESCRIPTION

[0025] The following is a further description of an abnormal electric field early warning method in a substation according to the present invention in conjunction with a specific embodiment.

[0026] Example

[0027] The early warning method for abnormal electric field in the substation in this embodiment includes the following steps:

[0028] Step 1: Two electric field collection points are set in the substation, namely the first electric field collection point and the second electric field collection point; the first voltage sensor and the second voltage sensor are set at the first electric field collection point and the second electric field collection point respectively; the first voltage sensor collects four voltage values ​​from the four layers of plates from top to bottom, namely The second voltage sensor collects four voltage values ​​from top to bottom through four layers of plates. ; Set the warning period T for abnormal electric field warning in the substation;

[0029] Step 2: Within an early warning period T, the first voltage sensor and the second voltage sensor both collect data once, and collect the collected data to form a first voltage data set U1 and a second voltage data set U2, as shown in the following formula (1):

[0030] (1)

[0031] In formula (1), They are four voltage values ​​collected by the first voltage sensor within the warning period T; They are four voltage values ​​collected by the second voltage sensor within the warning period T;

[0032] Step 3: Substitute all the data in the first voltage data set U1 into the following formula (2) and perform triple differential conditioning to obtain the voltage of the first electric field collection point collected by the first voltage sensor within the warning period T: ,

[0033] (2)

[0034] In formula (2), are the first, second and third difference conditioning coefficients, all of which are empirical values;

[0035] According to the voltage of the first electric field collection point Calculate the first electric field intensity at the first electric field collection point within the warning period T , as shown in the following formula (3),

[0036] (3)

[0037] In formula (3), is the dielectric constant of air; are the metal effective areas of the four plates of the first voltage sensor; R m11 is the sampling resistance value between the first plate and the second plate of the first voltage sensor; R m12 is the sampling resistance value between the third plate and the fourth plate of the first voltage sensor;

[0038] Step 4: Repeat the principle of step 3 to calculate the second electric field strength at the second electric field collection point within the warning period T ;

[0039] The first electric field strength and the second electric field strength Substitute it into the following formula (4) to make a judgment:

[0040] (4)

[0041] If formula (4) is satisfied, it means that there is an abnormal electric field in the substation, and an alarm is issued;

[0042] If formula (4) is not satisfied, proceed to step 5;

[0043] Step 5: Set the first electric field strength and the second electric field strength Substitute it into the following formula (5) to make a judgment:

[0044] (5)

[0045] If formula (5) is satisfied, it means that there is an abnormal electric field in the substation, and an alarm is issued;

[0046] If formula (5) is not satisfied, it means that there is no abnormality in the substation within the warning period T.

Claims

1. A method for early warning of abnormal electric field in a substation, characterized by: The following steps are involved: Step 1: two electric field collection points are set in the substation, namely the first electric field collection point and the second electric field collection point; A first voltage sensor and a second voltage sensor are respectively arranged at the first electric field collection point and the second electric field collection point; the first voltage sensor collects four voltage values ​​from the four layers of plates from top to bottom, which are The second voltage sensor collects four voltage values ​​from top to bottom by four layers of plates. ; Set the warning period T for abnormal electric field warning in the substation; Step 2: Within one warning cycle T, the first voltage sensor and the second voltage sensor both collect data once, and collect the collected data to form a first voltage data set U1 and a second voltage data set U2, as shown in the following formula (1): （1） In formula (1), are four voltage values ​​collected by the first voltage sensor within the warning period T; are four voltage values ​​collected by the second voltage sensor within the warning period T; Step 3: Substitute all the data in the first voltage data set U1 into the following formula (2) and perform triple differential conditioning to obtain the voltage of the first electric field collection point collected by the first voltage sensor within the warning period T: , （2） In formula (2), are the first, second and third difference conditioning coefficients, all of which are empirical values; According to the voltage of the first electric field collection point Calculate the first electric field strength of the first electric field collection point within the warning period T , as shown in the following formula (3), （3） In formula (3), is the dielectric constant of air; are the metal effective areas of the four plates of the first voltage sensor; R m11 is the sampling resistance value between the first electrode plate and the second electrode plate of the first voltage sensor; R m12 is the sampling resistance value between the third plate and the fourth plate of the first voltage sensor; Step 4: Repeat the principle of step 3 to calculate the second electric field strength of the second electric field collection point within the warning period T ; The first electric field strength and the second electric field strength Substitute it into the following formula (4) to make a judgment: （4） If formula (4) is satisfied, it means that there is an abnormal electric field in the substation, and an alarm is issued; If formula (4) is not satisfied, proceed to step 5; Step 5: Set the first electric field strength and the second electric field strength Substitute it into the following formula (5) to make a judgment: （5） If formula (5) is satisfied, it means that there is an abnormal electric field in the substation, and an alarm is issued; If formula (5) is not satisfied, it means that there is no abnormality in the substation within the warning period T.

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