Early Warning Method for Abnormal Electric Field in Substation

Abstract

The present invention specifically relates to a method for warning of abnormal electric fields in a substation, belonging to the technical field of power equipment warning. In the substation of the present invention, two electric field acquisition points are set, and then voltage acquisition is carried out on the two electric field acquisition points respectively through voltage sensors with four layers of electrode plates. The four acquired voltage data are processed by three-stage differential conditioning to eliminate the electromagnetic interference of the voltage sensors themselves and the substation environment, making the voltage data acquired by the voltage sensors more accurate and improving the warning accuracy of abnormal electric fields in the substation. The present invention adopts a method for comprehensively judging abnormal electric fields based on the electric field intensities at two points in the substation, eliminating the false warnings and missed warnings that may be brought by single-point warning and increasing the warning accuracy of abnormal electric fields in the substation.

Description

Technical Field

[0001] The present invention specifically relates to a method for warning of abnormal electric fields in a substation, belonging to the technical field of power equipment warning. Background Art

[0002] For substations of power grids below 220 kV, unattended operation has become the norm, and for substations of power grids above 500 kV, the trend of having fewer on-site operators is gradually emerging. These trends have imposed higher requirements on the operation, maintenance, and repair of equipment in substations. Regular or condition-based maintenance of equipment often requires entry into the substation. When carrying out maintenance work, the area near the power-off area is often a live area. To ensure the personal safety of maintenance personnel, it is necessary to detect and warn of abnormal electric fields in the substation to protect the maintenance personnel. Most of the existing methods for detecting and warning of abnormal electric fields in substations use electric field sensors to detect the electric field intensity. If the detected electric field intensity is higher than the threshold, an alarm is issued. However, due to the significant impact of electromagnetic interference in the substation on the accurate measurement of electric field sensors, the detection accuracy of abnormal electric field intensity in the substation is relatively low, which is prone to causing 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 a substation

[0004] To solve the above technical problem, the technical solution proposed by the present invention is: a method for warning of abnormal electric fields in a substation, comprising the following steps:

[0005] Step 1: Set two electric field acquisition points in the substation, namely the first electric field acquisition point and the second electric field acquisition point; set a first voltage sensor and a second voltage sensor at the first electric field acquisition point and the second electric field acquisition point respectively; the first voltage sensor consists of four layers of plates from top to bottom to collect four voltage values, which are ; the second voltage sensor consists of four layers of plates from top to bottom to collect four voltage values, which are ; set a warning period T for warning of abnormal electric fields in the substation once.

[0006] Step 2: Within one warning period T, both the first voltage sensor and the second voltage sensor perform data acquisition once, and the collected data are respectively collected 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 the 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 respectively;

[0009] Step 3: Substitute all the data in the first voltage dataset U1 into the following formula (2) for three - order difference conditioning to obtain the voltage of the first electric - field acquisition 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 respectively, and they are all empirical values;

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

[0013] (3)

[0014] In formula (3), is the air permittivity; are the metal effective areas of the four plates of the first voltage sensor respectively; 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;

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

[0016] Substitute the first electric - field strength and the second electric - field strength into the following formula (4) for judgment,

[0017] (4)

[0018] If the formula (4) is satisfied, it indicates that there is an abnormal electric - field situation in the substation, and an alarm is issued at this time;

[0019] If the formula (4) is not satisfied, continue to execute Step 5;

[0020] Step 5: Substitute the first electric - field strength and the second electric - field strength into the following formula (5) for judgment,

[0021] (5)

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

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

[0024] Advantages of the present invention: 1. Two electric field acquisition points are set in the substation in the present invention, and then voltage acquisition is carried out through voltage sensors with four layers of plates at the two electric field acquisition points respectively. The four collected voltage data are processed by three-level differential conditioning to eliminate the electromagnetic interference of the voltage sensor itself and the substation environment, making the voltage data collected by the voltage sensor more accurate and improving the early warning accuracy of abnormal electric fields in the substation. 2. The present invention adopts a method of comprehensively judging abnormal electric fields based on the electric field intensities at two points in the substation, eliminating the false alarms and missed alarms that may be caused by single-point early warning, and increasing the early warning accuracy of abnormal electric fields in the substation. Specific embodiments

[0025] The following further illustrates a method for early warning abnormal electric fields in a substation according to the present invention in conjunction with specific embodiments

[0026] Embodiment

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

[0028] Step 1: Set two electric field acquisition points in the substation, namely the first electric field acquisition point and the second electric field acquisition point; set a first voltage sensor and a second voltage sensor at the first electric field acquisition point and the second electric field acquisition point respectively; the first voltage sensor collects four voltage values from four layers of plates from top to bottom, which are ; the second voltage sensor collects four voltage values from four layers of plates from top to bottom, which are ; set an early warning period T for early warning abnormal electric fields in the substation once.

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

[0030] (1)

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

[0032] Step 3: Substitute all the data in the first voltage dataset U1 into the following formula (2) for three - order difference conditioning to obtain the voltage of the first electric - field acquisition 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 respectively, and they are all empirical values;

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

[0036] (3)

[0037] In formula (3), is the air permittivity; are the metal effective areas of the four plates of the first voltage sensor respectively; 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 calculation in Step 3 to obtain the second electric - field intensity of the second electric - field acquisition point within the warning period T ;

[0039] Substitute the first electric - field intensity and the second electric - field intensity into the following formula (4) for judgment,

[0040] (4)

[0041] If the formula (4) is satisfied, it indicates that there is an abnormal electric - field situation in the substation, and an alarm is issued at this time;

[0042] If the formula (4) is not satisfied, continue to execute Step 5;

[0043] Step 5: Substitute the first electric - field intensity and the second electric - field intensity into the following formula (5) for judgment,

[0044] (5)

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

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

Claims

1. A method for warning of abnormal electric fields in a substation, characterized in that: Including the following steps: Step 1: Set two electric field acquisition points in the substation, namely the first electric field acquisition point and the second electric field acquisition point; A first voltage sensor and a second voltage sensor are respectively arranged at the first electric field acquisition point and the second electric field acquisition point; the first voltage sensor is composed of four layers of plates from top to bottom to collect four voltage values which are respectively ; the second voltage sensor is composed of four layers of plates from top to bottom to collect four voltage values which are respectively ; Set an early warning cycle T for abnormal electric field early warning in the substation; Step 2: Within one said early warning cycle T, both the first voltage sensor and the second voltage sensor perform data acquisition once, and the collected data are respectively formed into 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 respectively four voltage values collected by the first voltage sensor within the warning period T; are respectively four voltage values collected by the second voltage sensor within the warning period T; Step 3: Substitute all the data in the first voltage dataset U1 into the following formula (2) for three - order difference conditioning to obtain the voltage of the first electric - field acquisition point collected by the first voltage sensor within the early - warning period T , （2） In formula (2), are the first, second, and third differential conditioning coefficients respectively, 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 air permittivity; are respectively 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; Step 4: Repeat the principle calculation in Step 3 to obtain the second electric field strength at the second electric field acquisition point within the warning period T ; Substitute the first electric field strength and the second electric field strength into the following formula (4) for judgment. （4） If formula (4) is satisfied, it indicates that there is an abnormal electric field situation in the substation, and an alarm is issued at this time; If formula (4) is not satisfied, continue to execute Step 5; Step 5: Substitute the first electric field strength and the second electric field strength into the following formula (5) for judgment. （5） If formula (5) is satisfied, it indicates that there is an abnormal electric field situation in the substation, and an alarm is issued at this time; If formula (5) is not satisfied, it indicates that there is no abnormal situation in the substation within the said early warning cycle T.

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