KR20220134321A - Capacitive accelerometer based partial discharge detection sensor and partial discharge detecting system - Google Patents

Abstract

According to the present invention, a partial discharge detection sensor based on a capacitive accelerometer method includes: a support frame attachable to a target in which partial discharge is detected; a magnetic material generating vibration by high frequency according to the partial discharge; an elastic material connecting the support frame and the magnetic material, and having elasticity; a variable capacitance means for varying capacitance according to a positional change of the magnetic material due to the vibration; and an output unit for outputting an electrical signal according to the change in the capacitance. Accordingly, the partial discharge can be effectively sensed while reducing the weight and volume of the sensor.

Description

Capacitive Accelerometer Method Partial Discharge Detection Sensor and Partial Discharge Detection System

The present invention relates to a capacitive accelerometer type partial discharge detection sensor using a permanent magnet and a partial discharge detection system having the same.

In general, electrical facilities such as GIS, GIB, transformers, switchboards, transmission/distribution cables, and rotating machines (motors, generators), which are electrical and power-related facilities, require high-voltage electricity to flow, so insulation is essential inside the facility. For this reason, a gas insulated switchgear called a GIS pipe is being applied.

Gas insulated switchgear (GIS) is a device that properly protects the system by safely opening and closing lines in abnormal conditions such as discharge, shock, accident, and short circuit as well as normal opening and closing for indoor and outdoor power plants and substations. Sulfur hexafluoride) gas-filled metal container has built-in opening and closing facilities such as disconnectors, grounding switches, and circuit breakers, as well as busbars. It is necessary to detect the failure of the gas insulated switchgear in advance and take action, and a method of predicting and measuring the partial discharge of the gas insulated switchgear as the most effective method is known and widely applied.

On the other hand, partial discharge is generated not only in the GIS but also in a transformer or high voltage transmission line, and it is necessary to detect partial discharge occurring in various places in the electric power field.

Partial discharge is a discharge phenomenon caused by partial dielectric breakdown caused by voids in a power transmission line through which a high voltage flows. In particular, partial discharge in the transmission line causes deterioration of the transmission line itself, and the instantaneous large current generated thereby may cause a decrease in power quality and, further, an overall failure of the transmission system. In order to detect such partial discharge before and after the partial discharge, various sensor technologies have been developed that can detect sudden changes in electromagnetic waves, emission of ultraviolet and sound waves, and thermal changes that occur during partial discharge.

In particular, changes in electromagnetic waves generated during partial discharge are easier to detect than other physical and chemical changes and are mainly used as signal sources for sensors for detecting partial discharge because the signal source has a greater strength. A representative example is HFCT (High Frequency Current Transformer). HFCT takes the form of a coil that completely wraps around the outside of the transmission line. When a time-varying magnetic field is formed outside the transmission line due to a sudden fault current in the transmission line, it is detected according to Faraday’s law. works with

However, HFCT has disadvantages in that a coil with a large number of turns must be used in order to improve the detection sensitivity, and accordingly, the weight of the sensor is heavy and the volume is large. Therefore, most of the existing HFCTs are limitedly installed at the end of the transmission line or transformer and used to detect the partial discharge signal. In the case of discharge, attenuation occurs in the process of signal propagation and finally falls to a level that the sensor cannot detect, and the HFCT cannot operate properly. Therefore, a partial discharge detection sensor that is light in weight and small in volume and can be directly attached in large quantities to the outside of the transmission line has been desired.

Republic of Korea Registration No. 10-2056241

An object of the present invention is to provide a partial discharge detection sensor capable of effectively detecting partial discharge while reducing weight and volume.

An object of the present invention is to provide a partial discharge position determination method capable of accurately determining a partial discharge position in a transmission line by directly attaching a large amount to a transmission line.

According to an aspect of the present invention, there is provided a capacitive accelerometer type partial discharge detection sensor, comprising: a support frame attachable to a partial discharge detection target; a magnetic material generating vibration by high frequency according to partial discharge; an elastic material connecting the support frame and the magnetic body and having elasticity; variable capacitance means for which the capacitance is changed according to a change in the position of the magnetic body due to vibration; and an output unit for outputting an electrical signal according to a change in the capacitance.

Here, the magnetic material may have a mass for generating vibration, and the elastic material may connect the support frame and the magnetic material such that an elastic modulus is applied.

Here, the mass and the elastic modulus may be set so that a natural frequency band of the magnetic material is similar to a band of 500 MHz to 1500 MHz.

Here, the variable capacitance means may include: a vibrating electrode extending from the magnetic body and vibrating along the magnetic body; and a detection electrode extending from the support frame in parallel to the vibrating electrode and having a capacitance varying according to a position of the vibrating electrode.

Here, the output unit may include a processor electrically connected to the detection electrode to detect a change in capacitance of the detection electrode.

Here, the magnetic material may include a permanent magnet for generating a magnetic field along a longitudinal direction of natural vibrations generated by the mass of the elastic material and the magnetic material.

Here, on the outer surface of the support frame, with respect to the partial discharge detection object in the form of a line, a means that can be attached to the partial discharge detection object may be formed so that the magnetic field direction of the internal magnetic material becomes the line direction. .

A partial discharge detection system according to another aspect of the present invention includes: capacitive accelerometer type partial discharge detection sensors attached to a plurality of points of a power transmission line; and a monitoring device that analyzes the sensing signals of the plurality of partial discharge detection sensors to determine whether partial discharge has occurred and a location where the partial discharge is generated.

Here, the partial discharge detection sensor may include: a support frame attachable to the power transmission line; a magnetic material generating vibration by high frequency according to partial discharge; an elastic material connecting the support frame and the magnetic body and having elasticity; variable capacitance means for which the capacitance is changed according to a change in the position of the magnetic body due to vibration; and an output unit for outputting an electrical signal according to a change in the capacitance.

Here, the monitoring device may include: designating two partial discharge detection sensors attached adjacently on the power transmission line; determining a position between attachment positions of the two partial discharge detection sensors as the occurrence position of the partial discharge from the absolute time difference of the partial discharge sensing signals of the two partial discharge detection sensors; determining a position before or after attachment positions of the two partial discharge detection sensors as a generation position of the partial discharge from the sign of the time difference of the partial discharge sensing signals; and shifting the designation of two partial discharge detection sensors adjacently attached on the power transmission line for a next determination according to the sign of the time difference of the partial discharge sensing signals.

Here, the partial discharge position determination method may further include calculating an accurate occurrence position of the partial discharge among positions between attachment positions of the two partial discharge detection sensors determined as the occurrence positions of the partial discharge. can

When the partial discharge detection sensor according to the spirit of the present invention having the above configuration is implemented, there is an advantage in that the partial discharge can be effectively detected while reducing the weight and volume of the attached sensor.

Specifically, it is a part of the capacitive accelerometer method using a permanent magnet proposed in the present invention, beyond the limiting points of the existing HFCT, which are the heavy weight and large volume of the sensor, and the limited installation at the end of the transmission line or the transformer. The discharge detection sensor can be miniaturized from several mm to several centimeters, and its weight can also be drastically reduced. It has the advantage of being able to accurately diagnose the source and prevent it in advance.

The partial discharge position determination method of the present invention has the advantage of being able to accurately determine the partial discharge position by directly attaching a large amount to a power transmission line or the like. This can achieve the advantage of enabling accurate initial diagnosis of partial discharge, which is considered the biggest problem in high-voltage DC transmission, in particular, in the trend that the transmission system is changing from high-voltage AC to high-voltage DC.

1 is a cross-sectional view showing an embodiment of a partial discharge detection sensor according to the spirit of the present invention.
FIG. 2 is a cross-sectional view illustrating an operating principle of the partial discharge detection sensor shown in FIG. 1;
3 is a block diagram illustrating an embodiment of a partial discharge detection system according to the spirit of the present invention.
4 is a flowchart illustrating an embodiment of a method for determining a partial discharge position for detecting an accurate position of a partial discharge according to the spirit of the present invention;

In describing the present invention, terms such as first, second, etc. may be used to describe various components, but the components may not be limited by the terms. The terms are only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.

When a component is referred to as being connected or connected to another component, it may be directly connected or connected to the other component, but it can be understood that other components may exist in between. .

The terms used herein are used only to describe specific embodiments, and are not intended to limit the present invention. The singular expression may include the plural expression unless the context clearly dictates otherwise.

In this specification, the terms include or include are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, and includes one or more other features or numbers, It may be understood that the possibility of the presence or addition of steps, operations, components, parts, or combinations thereof is not precluded in advance.

In addition, shapes and sizes of elements in the drawings may be exaggerated for clearer description.

The present invention is a method that can effectively detect partial discharge while reducing the weight and volume of the sensor, A capacitive accelerometer type partial discharge detection sensor using a permanent magnet) is presented.

When the partial discharge detection sensor of the above method is applied to a power transmission line, more specifically, an HVDC transmission line, the permanent magnet vibrates by a sudden change in the magnetic field outside the transmission line caused by the partial discharge, and static electricity induced by the permanent magnet vibration The capacity change can be detected as a partial discharge of the HVDC transmission line through a microprocessor.

In addition, if the partial discharge position detection system is constructed using the capacitive accelerometer type partial discharge sensors according to the spirit of the present invention, the position of the partial discharge generated in the power transmission line, more specifically, the HVDC transmission line can be accurately determined. A specific method of determining the partial discharge position will be described later.

1 is a cross-sectional view illustrating an embodiment of a partial discharge detection sensor according to the spirit of the present invention.

The illustrated partial discharge detection sensor includes: a support frame 110 that can be attached to a partial discharge detection target; Permanent magnet 140 as a magnetic material for generating vibration by high frequency according to partial discharge; a spring 120 as an elastic material connecting the support frame and the magnetic body and having elasticity; variable capacitance means for which the capacitance is changed according to a change in the position of the magnetic body due to vibration; and an output unit (not shown) for outputting an electrical signal according to a change in the capacitance.

The illustrated partial discharge detection sensor uses a permanent magnet 140 instead of a weight in a general capacitive accelerometer method. Accordingly, the permanent magnet 140 has a significant mass to generate vibration, and the spring 120 connects the support frame and the permanent magnet so that an elastic modulus is applied.

On the other hand, the illustrated structure may have a natural frequency for vibration of the permanent magnet 140 according to the elastic modulus and the mass of the permanent magnet. do. In other words, the mass and the elastic modulus may be set such that a natural frequency band for vibration of the permanent magnet 140 is similar to a band of 500 MHz to 1500 MHz. For example, the 3dB cutoff band of the natural frequency curve determined by the elastic modulus (k) and the mass (m) may be set to be a band of 500 MHz to 1500 MHz.

In FIG. 1, the variable capacitance means includes: a vibrating electrode 150 extending from the permanent magnet and vibrating along the permanent magnet; and a detection electrode 160 extending from the support frame 110 in parallel to the vibrating electrode 150 and having a capacitance varying according to a position of the vibrating electrode.

Since it is difficult to manufacture the permanent magnet in a protruding form, in FIG. 1 , the permanent magnet 140 is embedded and the vibration electrode 150 further includes an internal support frame 130 extending to the outside.

The output unit of the partial discharge detection sensor of the present invention may include a processor electrically connected to the detection electrode 160 to detect a change in capacitance of the detection electrode.

In the partial discharge detection sensor of the present invention having a variable capacitance structure formed by the vibration electrode 150 and the detection electrode 160 as shown, when the permanent magnet vibrates according to a sudden magnetic field change outside the transmission line, it is fixedly connected to the permanent magnet The vibrating electrode 150 also vibrates, and the output unit detects a difference in capacitance (or change in capacitance) between different detection electrodes 160 fixed to the external support frame, thereby generating a magnetic field generated during partial discharge. It is possible to measure the abrupt change in indirectly and precisely.

In other words, the change in capacitance between the flat electrode 160 attached to the outer support frame 110 and the flat electrode 150 connected to the inner support frame 130 is partially discharged of the HVDC transmission line through the microprocessor of the output unit. can be detected as

In FIG. 1 , two detection electrodes 160 are disposed before and after the vibrating electrode 150 , whereas in other implementations, only one detection electrode disposed parallel to the vibrating electrode may be provided. In this case, the output unit may be respectively connected to the vibration electrode and the detection electrode to detect a change in capacitance between the two electrodes.

The magnetic body of the partial discharge detection sensor of the present invention is implemented as a permanent magnet 140 that generates a magnetic field along the longitudinal direction of the natural vibration generated by the spring 120 and the mass of the magnetic body. In another implementation, an electromagnet that generates a magnetic field in the above-described direction may be substituted, but there is a disadvantage in securing power. In another implementation, a magnetic material in which a permanent magnetic field is not formed may be substituted, but in this case, there is a disadvantage in that the sensing sensitivity is lowered.

In order to maintain the magnetic field direction of the above-described magnetic material with respect to the power transmission line to be measured, the outer surface (more precisely, the bottom surface) of the support frame 110 has an inner A means that can be attached to the partial discharge detection target (eg, a guide groove suitable for a diameter of the transmission line) may be formed so that the magnetic field direction of the magnetic material becomes the lengthwise direction of the transmission line.

Next, the overall operation principle of the illustrated partial discharge detection sensor will be specifically exemplified.

FIG. 2 is a cross-sectional view illustrating an operation principle of the partial discharge detection sensor shown in FIG. 1 .

When a change in the magnetic field occurs outside the sensor, the permanent magnet 140 in the outer support frame 110 and the inner support frame 130 connected by the spring 120 vibrates in the direction of the external magnetic field. When the permanent magnet 140 vibrates, the vibration electrode 150 connected to the inner support frame 130 vibrates accordingly. The capacitance between the vibration electrode 150 and the detection electrode 160 in the parallel direction is changed as the vibration electrode 150 vibrates according to Equation 1 below.

Among the two detection electrodes 160 , the electrostatic capacity increases according to Equation 1 for the side having the closer inter-electrode distance, and the electrostatic capacity decreases for the side with the greater distance from the two detection electrodes 160 according to Equation 1 above. By reading this change in capacitance through the microprocessor of the output unit, the vibration of the permanent magnet 140 is sensed, and partial discharge of the transmission line can be predicted by estimating it inversely.

Next, a partial discharge detection system that performs a method of determining a detection position of a partial discharge generated in a power transmission line as a power transmission line according to the spirit of the present invention will be described.

3 is a block diagram illustrating an embodiment of a partial discharge detection system according to the spirit of the present invention.

The illustrated partial discharge detection system includes: capacitive accelerometer type partial discharge detection sensors 101 to 10N attached to a plurality of points of the power transmission line P as a power transmission line; and a monitoring device 400 that analyzes the sensing signals of the plurality of partial discharge detection sensors 101 to 10N to determine whether partial discharge has occurred and a location where the partial discharge occurs.

The partial discharge detection sensors 101 to 10N may be applied as partial discharge sensors shown in FIG. 1 .

The illustrated monitoring device 400 may include a storage unit 450 that stores sensing signals of the plurality of partial discharge detection sensors 101 to 10N and/or information necessary for partial discharge determination. For example, the attachment order and attachment position values of the plurality of partial discharge detection sensors 101 to 10N on the power transmission line P may be stored.

In the case of an implementation to reduce the amount of communication, the output units 171 to 17N provided in each of the partial discharge detection sensors 101 to 10N analyze each sensing signal to determine whether a partial discharge signal is present, and convert the partial discharge signal to the partial discharge signal. Only the determined sensing signals may be transmitted to the monitoring device 400 .

The illustrated partial discharge detection system detects the exact position of the partial discharge by a predetermined algorithm by installing a plurality of sensors at equal intervals on a power transmission line. At this time, the sensor attached (installed) to the transmission line P applies a capacitance change detection method, which has a strong advantage against electromagnetic noise frequently generated in an outdoor transmission line.

Next, an algorithm for detecting the exact position of the partial discharge performed by the monitoring device 400 will be described.

4 is a flowchart illustrating an embodiment of a method for determining a partial discharge position for detecting an accurate position of a partial discharge according to the spirit of the present invention.

designating two partial discharge detection sensors attached adjacently on the illustrated power transmission line; determining a location between attachment positions of the two partial discharge detection sensors as the generation location of the partial discharge from the absolute time difference of the partial discharge sensing signals of the two partial discharge detection sensors (S120); determining a position before or after attachment positions of the two partial discharge detection sensors as a generation position of the partial discharge from the sign of the time difference of the partial discharge sensing signals (S160); and shifting the designation of two partial discharge detection sensors adjacently attached on the power transmission line for the next determination according to the sign of the time difference of the partial discharge sensing signals (S172, S174).

In addition, the illustrated partial discharge position determination method includes the steps of calculating an accurate occurrence position of the partial discharge among positions between attachment positions of the two partial discharge detection sensors determined as the occurrence positions of the partial discharge (S140, S145) may be further included.

The symbols applied to each of the equations described in the illustrated flowchart are defined as follows.

t(S _N ) : arrival time of the partial discharge signal arriving at the Nth sensor

l : distance between two adjacent sensors

v : speed of partial discharge signal

P _PD : Location of partial discharge

: N 번째 센서의 위치

: Position of the Nth sensor

x : distance from the Nth sensor

In the partial discharge detection system shown in FIG. 3, partial discharge detection sensors as shown in FIG. 1 are attached to a power line at regular intervals, and partial discharge sensing signals are transmitted (received) from the partial discharge detection sensors attached to the power line. 1) The monitoring device first designates (discriminates) those of two adjacent partial discharge detection sensors among the transmitted sensing signals (that is, the step of designating the two partial discharge detection sensors). In the drawing, the N-th and N+1-th sensors are designated.

이면, 부분 방전은 그 두 센서 사이에서 발생하지 않은 것이다. In the illustrated step S120, the difference in arrival time of the partial discharge signal reaching the N-th and N+1-th sensors is

If this is the case, then the partial discharge has not occurred between the two sensors.

In the illustrated steps S120 and S160, if the difference between the arrival times of the partial discharge signals arriving at the N-th sensor and the N+1-th sensor is positive, the partial discharge occurs on the right side of the N+1-th sensor. Accordingly, since it is necessary to check the arrival time difference between the N+1-th and N+2th sensors, the partial discharge confirmation target sensor is changed (shifted) to the N+1-th (S172). In this process, the N value is sequentially increased by 1 until the determination result of step S120 is false.

At this time, if the difference between the arrival times of the partial discharge signals arriving at the Nth and N+1th sensors is negative, the partial discharge occurred on the left side of the Nth sensor, so check the difference in arrival times of the N-1th and Nth sensors. and the partial discharge confirmation target sensor is changed (shifted) to the N-1th (S174). In this process, the N value is sequentially decreased by 1 until the determination result of step S120 is false.

이 아니면, 부분 방전은 N 번째와 N+1 번째 센서 사이에서 발생한 것으로 판정할 수 있으며(S140), 부분 방전은 N번째 센서의 위치에서 도시한 S140 단계 내의 수식에서 구한 x값 만큼 오른쪽에 위치에서 발생한 것으로 추정할 수 있다(S145). In the illustrated step S120, if the difference in arrival time of the partial discharge signal reaching the Nth and N+1th sensors is

Otherwise, it can be determined that the partial discharge has occurred between the Nth sensor and the N+1th sensor (S140), and the partial discharge occurs at the position to the right by the x value obtained from the equation in step S140 shown at the position of the Nth sensor. It can be estimated that it has occurred (S145).

Those skilled in the art to which the present invention pertains should understand that the present invention may be embodied in other specific forms without changing the technical spirit or essential characteristics thereof, so the embodiments described above are illustrative in all respects and not restrictive. only do The scope of the present invention is indicated by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention. .

110: support frame
120: spring
130: inner support frame
140: permanent magnet
150: vibrating electrode
160: detection electrode

Claims (11)

a support frame that can be attached to a partial discharge detection target;
a magnetic material generating vibration by high frequency according to partial discharge;
an elastic material connecting the support frame and the magnetic body and having elasticity;
variable capacitance means for which the capacitance is changed according to a change in the position of the magnetic body due to vibration; and
An output unit for outputting an electrical signal according to a change in the capacitance
A capacitive accelerometer-type partial discharge detection sensor comprising a.
According to claim 1,
The magnetic material has a mass that generates vibration,
The elastic material is a capacitive accelerometer type partial discharge detection sensor for connecting the support frame and the magnetic body so that an elastic modulus is applied.
3. The method of claim 2,
The mass and the elastic modulus are set such that a natural frequency band of the magnetic material is similar to a band of 500 MHz to 1500 MHz.
According to claim 1,
The variable capacitance means,
a vibrating electrode extending from the magnetic body and vibrating along the magnetic body; and
A detection electrode extending from the support frame parallel to the vibrating electrode and having a capacitance varying according to a position of the vibrating electrode
A capacitive accelerometer type partial discharge detection sensor comprising a.
5. The method of claim 4,
the output unit,
and a processor electrically connected to the detection electrode and configured to detect a change in capacitance of the detection electrode.
The method of claim 1,
The magnetic body is
A permanent magnet for generating a magnetic field along the longitudinal direction of natural vibrations generated by the mass of the elastic material and the magnetic material
A capacitive accelerometer type partial discharge detection sensor comprising a.
7. The method of claim 6,
On the outer surface of the support frame,
A capacitive accelerometer type partial discharge detection sensor is provided with means that can be attached to the partial discharge detection object so that the magnetic field direction of the magnetic material inside becomes the line direction with respect to the partial discharge detection object in the form of a line.
capacitive accelerometer-type partial discharge detection sensors attached to multiple points of the power transmission line; and
A monitoring device that analyzes the sensing signals of the plurality of partial discharge detection sensors to determine whether partial discharge has occurred and the location of the partial discharge
Partial discharge detection system comprising a.
9. The method of claim 8,
The partial discharge detection sensor,
a support frame attachable to the power transmission line;
a magnetic material generating vibration by high frequency according to partial discharge;
an elastic material connecting the support frame and the magnetic body and having elasticity;
variable capacitance means for which the capacitance is changed according to a change in the position of the magnetic body due to vibration; and
An output unit for outputting an electrical signal according to a change in the capacitance
Partial discharge detection system comprising a.
9. The method of claim 8,
The monitoring device is
designating two partial discharge detection sensors adjacently attached on the power transmission line;
determining a position between attachment positions of the two partial discharge detection sensors as the occurrence position of the partial discharge from the absolute time difference of the partial discharge sensing signals of the two partial discharge detection sensors;
determining a position before or after attachment positions of the two partial discharge detection sensors as a generation position of the partial discharge from the sign of the time difference of the partial discharge sensing signals; and
shifting the designation of two partial discharge detection sensors adjacently attached on the power transmission line for a next determination according to a sign of the time difference of the partial discharge sensing signals;
Partial discharge detection system for performing a partial discharge position determination method comprising a.
11. The method of claim 10,
The partial discharge position determination method comprises:
calculating an accurate occurrence position of the partial discharge among positions between attachment positions of the two partial discharge detection sensors determined as the occurrence positions of the partial discharge
Partial discharge detection system further comprising a.

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