CN112305392A - Partial discharge source positioning system, positioning method and partial discharge detection equipment - Google Patents

Abstract

The invention relates to the field of high-voltage electrical appliances, in particular to a partial discharge source positioning system, which comprises partial discharge detection equipment, and first capacitive equipment 2 which is connected with a power transformer 1 and comprises a capacitor C1 and a capacitor C2, wherein the capacitor C1 and the capacitor C2 are arranged in the power transformer and are sequentially connected between a bus and a ground GND in series; the capacitor C3 and the capacitor C4 are sequentially connected between the bus and the ground GND in series; the sensor T1 is coupled on a conductor connecting the power transformer 1 and the bus, and the two ends of the sensor T1, the two ends of the capacitor C2 and the two ends of the capacitor C4 are respectively connected with partial discharge detection equipment; the partial discharge detection equipment identifies external interference or positions the position of a partial discharge source according to the polarities of a voltage signal U1, a voltage signal U2 and a voltage signal U3 which are respectively output by the partial discharge detection equipment; the system of the invention is beneficial to efficiently positioning the unknown occurrence of the partial discharge fault, thereby improving the efficiency of overhauling and maintaining operation. The invention also relates to a partial discharge source positioning method and partial discharge detection equipment applying the method.

Description

Partial discharge source positioning system, positioning method and partial discharge detection equipment

Technical Field

The invention belongs to the field of high-voltage electrical appliances, and relates to a partial discharge source positioning system, a positioning method and partial discharge detection equipment.

Background

Partial discharge of a transformer is a common type of fault in power transformers. Refers to the non-penetrating discharge which occurs at the edge of a transformer gap, a conductor and an oil film under the condition of high voltage. The partial discharge of the transformer can generate an accumulation effect to cause the aging of transformer components, and the method is an important fault type influencing the stable operation and the normal state of the transformer.

The method for measuring the partial discharge of the transformer is divided into an electrical measurement method and a non-electrical measurement method, and the electrical measurement method is high in sensitivity and widely applied. The principle of the electrical measurement is that each partial discharge of the transformer is accompanied by a certain amount of charge causing a voltage change on the outer electrode of the test specimen through the dielectric. The time of each discharge is very short, the time of each discharge in the air gap is in the order of 10ns, the time of each discharge in the oil gap is only 1ms, and the short-time pulse can generate a high-frequency electromagnetic signal to radiate outwards. The electrical measurement method is based on these principles to perform the detection. The electrical measurement method includes a pulse current method, a radio interference voltage method, a dielectric loss analysis method, and the like.

The pulse current method is widely used for measuring voltage (instantaneous) change or pulse current change generated at two ends of a sample caused by partial discharge. Detection is achieved by detecting the impedance access to the measurement loop. The principle is that when one internal partial discharge occurs in the transformer, a discharge pulse current is generated, when the pulse current passes through a grounding loop formed by a coupling capacitor and a detection impedance, a voltage is generated at two ends of the detection impedance, the voltage is in direct proportion to the magnitude of the partial discharge of the transformer, and the pulse voltage can be calculated specifically to obtain the corresponding partial discharge of the transformer.

However, when the partial discharge detection of the transformer is performed under the operation condition, the partial discharge detection of the transformer is inevitably affected by the partial discharge of other power equipment in the transformer substation and external interference noise (for example, external interference current), and in the prior art, the partial discharge detected by the bushing or the cable terminal is regarded as the partial discharge of the transformer by performing the partial discharge detection of the transformer through the bushing, the cable terminal and the like of the capacitive equipment connected with the transformer, and the detection method has certain practicability.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides an office discharge source positioning system which can identify external interference current and position the location of an office discharge source.

In order to achieve the purpose, the invention adopts the following technical scheme:

a partial discharge source positioning system comprises partial discharge detection equipment and first capacitive equipment 2 connected with a power transformer 1, wherein the first capacitive equipment 2 comprises a capacitor C1 and a capacitor C2 which are arranged in the first capacitive equipment 2 and sequentially connected in series between a bus and a ground GND (ground), and the partial discharge source positioning system further comprises a capacitor C3 and a capacitor C4 which are sequentially connected in series between the bus and the ground GND;

the sensor T1 is coupled on a conductor connecting the power transformer 1 and the bus, the output end of the sensor T1 is connected with the partial discharge detection equipment to output a voltage signal U1, the two ends of the capacitor C2 are respectively connected with the partial discharge detection equipment to output a voltage signal U2, and the two ends of the capacitor C4 are respectively connected with the partial discharge detection equipment to output a voltage signal U3; the partial discharge detection equipment identifies the position of an external interference or a positioning partial discharge source according to the polarities of the voltage signal U1, the voltage signal U2 and the voltage signal U3.

Preferably, the partial discharge source positioning system further includes a signal coupling device SCU1, a signal coupling device SCU2 and a signal coupling device SCU3, an output end of the sensor T1 is connected with the signal coupling device SCU1, two ends of a capacitor C2 are respectively connected with the signal coupling device SCU2, two ends of a capacitor C4 are respectively connected with the signal coupling device SCU3, the signal coupling device SCU1, the signal coupling device SCU2 and the signal coupling device SCU3 are respectively connected with the partial discharge detection apparatus for collecting a voltage signal U1, a voltage signal U2 and a voltage signal U3;

the signal coupling device SCU1, the signal coupling device SCU2, the signal coupling device SCU3 and the partial discharge detection equipment are mutually independent equipment; alternatively, the signal coupling device SCU1, the signal coupling device SCU2, the signal coupling device SC3 and the partial discharge source detecting device are an integrated device.

Preferably, the capacitor C3 and the capacitor C4 are also arranged in the first capacitive device 2.

Preferably, the capacitor C3 and the capacitor C4 are arranged within the second capacitive device 3.

Preferably, the first capacitive device 2 includes an insulating core having a capacitance voltage-dividing insulating structure, a plurality of capacitance screens alternately disposed with the insulating layer are embedded in the insulating core, and the capacitance C1, the capacitance C2, the capacitance C3 and the capacitance C4 are all embedded in the insulating core and are all composed of a plurality of capacitance screens embedded in the insulating core.

Preferably, the first capacitive device 2 is a bushing, a lightning arrester, a current transformer, a voltage transformer or a cable termination.

Preferably, the first capacitive device 2 is a bushing, the bushing further includes a primary conductor 20 and an insulating core wrapped around the primary conductor 20, the primary conductor 20 is connected to the power transformer 1, and the sensor T1 is coupled to the primary conductor 20; the capacitor C1, the capacitor C2, the capacitor C3 and the capacitor C4 are embedded in the insulating core body, the two ends of the insulating core body are respectively provided with an upper flange 22 and a lower flange 23, and the middle part of the insulating core body is provided with a mounting flange 15; the capacitor C1 is composed of a plurality of coaxial capacitor screens which are alternately arranged with insulating layers and have gradually increased diameters and gradually shortened lengths, the capacitor C2 is a tap capacitor of the capacitor C1, or the capacitor C2 is composed of a group of capacitor screens which are arranged outside the capacitor screen at the outermost side of the capacitor C1 and are connected in parallel; the capacitor C3 is composed of a group of mutually insulated and mutually overlapped capacitor screens arranged outside the capacitor screen of the corresponding capacitor C1 from one end of the upper flange 12 to the grounding end of the mounting flange 15 along the axial direction, the capacitor C4 is a tap capacitor of the capacitor C3, or the capacitor C4 is composed of a group of capacitor screens arranged outside the outermost capacitor screen of the capacitor C3 in parallel.

Preferably, the first capacitive device 2 and the second capacitive device 3 are any two of a bushing, an arrester, a current transformer, a voltage transformer, a cable terminal or a cable middle head, respectively.

Preferably, the first capacitive device 2 is a bushing and the second capacitive device 3 is a lightning arrester.

Preferably, the bushing further comprises a primary conductor 20 and an insulating core wrapped around the outside of the primary conductor 20, the primary conductor 20 is connected to the power transformer 1, and the sensor T1 is coupled to the primary conductor 20; the capacitor C1 and the capacitor C2 are embedded in the insulating core, the capacitor C1 is a main insulating capacitor and consists of a plurality of coaxial capacitor screens which are gradually increased in diameter and gradually shortened in length and are alternately arranged with the insulating layers; the capacitor C2 is a tap capacitor of the capacitor C1, or the capacitor C2 is formed by connecting a group of capacitor screens in parallel outside the capacitor screen at the outermost side of the capacitor C1.

Preferably, the second capacitive device 3 is an arrester, the arrester includes a valve plate core body formed by stacking a plurality of valve plates and an insulating core body sleeved outside the valve plate core body, the capacitor C3 and the capacitor C4 are formed by valve plates of the arrester, the capacitor C3 is formed by sequentially stacking a plurality of valve plates, and the capacitor C4 is formed by stacking at least one valve plate below the plurality of valve plates of the capacitor C3.

Preferably, the second capacitive device 3 is an arrester, the arrester includes a valve plate core body formed by stacking a plurality of valve plates and an insulating core body sleeved outside the valve plate core body, the capacitor C3 and the capacitor C4 are both embedded in the insulating core body, and the capacitor C3 is composed of a string of mutually insulated and mutually overlapped capacitor screens arranged from one end of the insulating core body to the other end; the capacitor C4 is a tap capacitor of the capacitor C3, or the capacitor C4 is formed by connecting a group of capacitor screens in parallel outside the outermost capacitor screen of the capacitor C3.

Preferably, if the polarity of the voltage signal U1 is opposite to the polarities of the voltage signal U2 and the voltage signal U3, it is determined that the partial discharge source is present in the power transformer 1; if the polarity of the voltage signal U2 is opposite to the polarities of the voltage signal U1 and the voltage signal U3, it is determined that the partial discharge source is present in the first capacitive device 2; if the polarities of the voltage signal U1, the voltage signal U2 and the voltage signal U3 are the same, it is determined that an external interference current occurs.

Preferably, the capacitor C3 and the capacitor C4 are also arranged in the first capacitive device 2; if the polarity of the voltage signal U3 is opposite to the polarity of the voltage signals U1 and U2, it is determined that the partial discharge source is present in the first capacitive device 2.

Preferably, the capacitor C3 and the capacitor C4 are arranged in the second capacitive device 3; if the polarity of the voltage signal U3 is opposite to the polarity of the voltage signals U1 and U2, it is determined that the partial discharge source is present in the second capacitive device 3.

A method for positioning a partial discharge source,

receiving a collected voltage signal U1 of the power transformer, and receiving a voltage signal U2 and a voltage signal U3 collected by a capacitive device connected with the power transformer;

when the partial discharge source is detected, if the polarity of the voltage signal U1 is opposite to the polarities of the voltage signal U2 and the voltage signal U3, judging that the partial discharge source exists in the power transformer;

if the polarity of the voltage signal U2 is opposite to the polarities of the voltage signal U1 and the voltage signal U3, judging that a partial discharge source exists in the capacitive equipment outputting the voltage signal U2;

if the polarity of the voltage signal U3 is opposite to the polarities of the voltage signal U1 and the voltage signal U2, judging that a partial discharge source exists in the capacitive equipment outputting the voltage signal U3;

if the polarities of the voltage signal U1, the voltage signal U2, and the voltage signal U3 are the same, it is determined as an external disturbance.

The partial discharge detection device comprises a processor, and the processor executes the partial discharge source positioning method.

The partial discharge source positioning system can detect the partial discharge source under the operation condition of the power transformer, can distinguish and eliminate external interference current and the partial discharge source, realizes the positioning of the partial discharge source, ensures the reliable and stable operation of the power transformer, is favorable for efficiently positioning the position of the occurrence of the partial discharge fault, and further improves the efficiency of maintenance and repair operation.

In addition, the partial discharge source positioning system adopts the existing capacitive equipment connected with the power transformer for detection, such as a sleeve, a lightning arrester, a current transformer, a voltage transformer, a cable terminal or a cable middle head, and does not need to add extra equipment, so that the partial discharge source positioning system is simple in structure and convenient to install and use.

The invention also provides partial discharge detection equipment with a partial discharge source positioning function and a partial discharge source positioning method.

Drawings

Fig. 1 is a schematic structural diagram of a first embodiment of a partial discharge source positioning system according to the present invention;

fig. 2 is a schematic structural diagram of a second embodiment of the partial discharge source positioning system according to the present invention;

FIG. 3 is a schematic circuit diagram of the partial discharge source positioning system of the present invention;

FIG. 4 is a schematic structural view of the bushing of the present invention;

fig. 5 is a schematic view of the structure of the arrester according to the present invention;

fig. 6 is a schematic structural view of another embodiment of the arrester according to the present invention;

fig. 7 is a schematic structural diagram of a module of the first embodiment of the partial discharge detection apparatus according to the present invention;

fig. 8 is a schematic block diagram of an office detection device according to a second embodiment of the present invention.

Detailed Description

The following further describes a specific embodiment of the partial discharge source positioning system according to the present invention with reference to the embodiments shown in fig. 1 to 3. The partial discharge source positioning system of the present invention is not limited to the description of the following embodiments.

The partial discharge source positioning system can be used for partial discharge detection of a power transformer, a power transformer 1 is equivalent to an equivalent capacitor C0 which is connected between a bus and a ground GND in series, the partial discharge source positioning system comprises partial discharge detection equipment and a first capacitive equipment 2 which is connected with the power transformer 1, the first capacitive equipment 2 comprises a capacitor C1 and a capacitor C2 which are arranged in the partial discharge source positioning system and are sequentially connected between the bus and the ground GND in series, and the partial discharge source positioning system also comprises a capacitor C3 and a capacitor C4 which are sequentially connected between the bus and the ground GND in series; the sensor T1 is coupled on a conductor connecting the power transformer 1 and the bus, the output end of the sensor T1 is connected with the partial discharge detection equipment to output a voltage signal U1, the two ends of the capacitor C2 are respectively connected with the partial discharge detection equipment to output a voltage signal U2, and the two ends of the capacitor C4 are respectively connected with the partial discharge detection equipment to output a voltage signal U3; the partial discharge detection equipment identifies the position of an external interference or a positioning partial discharge source according to the polarities of the voltage signal U1, the voltage signal U2 and the voltage signal U3. Under normal conditions, voltage signal U1, voltage signal U2 and voltage signal U3 are power frequency voltage signals, when external interference current I1 or partial discharge occurs, voltage signal U1, voltage signal U2 and voltage signal U3 can produce the pulse voltage signal that is different from power frequency voltage signal, and partial discharge detection equipment only needs to gather voltage signal U2 at both ends of electric capacity C2 or voltage signal U3 or voltage signal U1 at both ends of electric capacity C4, can realize the detection of partial discharge source, and this belongs to the prior art, and no longer repeated here. The prior art partial discharge detection device cannot determine whether the detected partial discharge source is from the power transformer or from the first capacitive device.

The partial discharge source positioning system can detect partial discharge of the power transformer and the capacitive equipment under the operation condition, can detect the partial discharge source under the operation condition of the power transformer, can distinguish and eliminate external interference current I1 and the partial discharge source through polarity judgment by acquiring a voltage signal U1 of the power transformer and voltage signals U2 and U3 of the two capacitive equipment connected with the power transformer, realizes that the partial discharge source is positioned from the transformer or the capacitive equipment, ensures the reliable and stable operation of the power transformer, is favorable for efficiently positioning the position where a partial discharge fault occurs, and further improves the efficiency of overhauling and maintenance operation.

The partial discharge source positioning system further comprises a signal coupling device SCU1, a signal coupling device SCU2 and a signal coupling device SCU3, the output end of the sensor T1 is connected with the signal coupling device SCU1, two ends of a capacitor C2 are respectively connected with the signal coupling device SCU2, two ends of a capacitor C4 are respectively connected with the signal coupling device SCU3, and the signal coupling device SCU1, the signal coupling device SCU2 and the signal coupling device SCU3 are respectively connected with partial discharge detection equipment and are respectively used for collecting a voltage signal U1, a voltage signal U2 and a voltage signal U3. It should be noted that the signal coupling unit SCU1, the signal coupling unit SCU2, the signal coupling unit SCU3 and the partial discharge detection device are independent devices. Or, the signal coupling device SCU1, the signal coupling device SCU2, the signal coupling device SCU3 and the partial discharge source detection device are an integrated device, and the signal coupling device SCU1, the signal coupling device SCU2 and the signal coupling device SCU3 are located in the partial discharge source detection device and connected with the capacitive device through wires, which is beneficial to reducing the number of components of the partial discharge source positioning system of the present invention, simplifying the wiring structure and improving the assembly efficiency. The signal coupling device SCU1, the signal coupling device SCU2, and the signal coupling device SCU3 are used for collecting power frequency voltage signals at two ends of a capacitor, and the implementation thereof belongs to the prior art in the field and is not described herein again.

Preferably, the capacitor C3 and the capacitor C4 are also arranged in the first capacitive device 2, i.e. the capacitors C1, C2, C3 and C4 are located in the same capacitive device. Further, the first capacitive device 2 may be a bushing, a lightning arrester, a Current Transformer (CT), a voltage transformer (PT), a cable terminal, etc., a device having an insulating core of a capacitive voltage dividing insulating structure. The insulating core body is embedded with a plurality of capacitive screens that set up with the insulating layer in turn, electric capacity C1, electric capacity C2, electric capacity C3 and electric capacity C4 all inlay and establish in the insulating core body, constitute by a plurality of capacitive screens of inlaying in the insulating core body.

Preferably, the capacitor C3 and the capacitor C4 are arranged in the second capacitive device 3, i.e. the capacitor C1 and the capacitor C2 are located in a separate capacitive device, and the capacitor C3 and the capacitor C4 are located in another separate capacitive device. For example, the first capacitive device 2 and the second capacitive device 3 are any two of a bushing, an arrester, a current transformer, a voltage transformer, a cable terminal or a cable middle head, respectively.

It should be noted that the capacitor C3 and the capacitor C4 may be disposed in neither the first capacitive device 2 nor the second capacitive device 3, but may be independent of the capacitances of the first capacitive device 2, the second capacitive device 3 and the power transformer 1. This, of course, requires the provision of additional capacitor equipment, which increases the difficulty of installation and maintenance.

Preferably, if the polarity of the voltage signal U1 output by the signal coupling device SCU1 is opposite to the polarity of the voltage signal U2 output by the signal coupling device SCU2 and the polarity of the voltage signal U3 output by the signal coupling device SCU3, it is determined that the partial discharge source is present inside the power transformer 1; if the polarity of the voltage signal U2 output by the signal coupling device SCU2 is opposite to the polarity of the voltage signal U1 output by the signal coupling device SCU1 and the polarity of the voltage signal U3 output by the signal coupling device SCU3, it is determined that the partial discharge source is present in the first capacitive device 2; if the polarities of the voltage signal U1 output by the signal coupling device SCU1, the voltage signal U2 output by the signal coupling device SCU2, and the voltage signal U3 output by the signal coupling device SCU3 are the same, it is determined that the external disturbance current I1 occurs.

Preferably, the capacitor C3 and the capacitor C4 are also arranged in the first capacitive device 2; if the polarity of the voltage signal U3 output by the signal coupling device SCU3 is opposite to the polarity of the voltage signal U1 output by the signal coupling device SCU1 and the polarity of the voltage signal U2 output by the signal coupling device SCU2, it is determined that the partial discharge source is present in the first capacitive device 2.

Preferably, the capacitor C3 and the capacitor C4 are arranged in the second capacitive device 3, and the second capacitive device 3 is connected with the power transformer 1; if the polarity of the voltage signal U3 output by the signal coupling device SCU3 is opposite to the polarity of the voltage signal U1 output by the signal coupling device SCU1 and the polarity of the voltage signal U2 output by the signal coupling device SCU2, it is determined that the partial discharge source is present in the second capacitive device 3.

The signal coupling devices SCU1, SCU2 and SCU3 are used for collecting voltage signals, and belong to the prior art, and are not described herein again.

Fig. 2 and 4 show a first embodiment of the partial discharge source positioning system according to the present invention.

In electrical performance, the power transformer 1 can be equivalently regarded as a capacitor, that is, an equivalent capacitor C0 serially connected between the bus and the ground GND, the power transformer 1 is provided with a first capacitive device 2, the first capacitive device 2 is a bushing, the capacitor C1, the capacitor C2, the capacitor C3 and the capacitor C4 are all arranged in the first capacitive device 2, that is, in the bushing, and the bushing further includes a primary conductor 20; the capacitor C1 and the capacitor C2 are sequentially connected between the bus and the ground GND in series, the constant volume C3 and the capacitor C4 are sequentially connected between the bus and the ground GND in series, the primary conductor 20 is connected with the power transformer 1, namely the primary conductor 20 and the equivalent capacitor C0 are sequentially connected between the bus and the ground GND in series; the partial discharge source positioning system comprises a sensor T1, a signal coupling device SCU1, a signal coupling device SCU2, a signal coupling device SCU3 and partial discharge detection equipment, wherein the sensor T1 is a Rogowski coil LS, the Rogowski coil LS is coupled on a primary conductor 20, the output end of the Rogowski coil LS is connected with the signal coupling device SCU1, two ends of a capacitor C2 are respectively connected with the signal coupling device SCU2, two ends of the capacitor C4 are respectively connected with the signal coupling device SCU3, and the signal coupling device SCU1, the signal coupling device SCU2 and the signal coupling device SCU3 are respectively connected with the partial discharge detection equipment.

When the partial discharge source positioning system detects, if the polarity of a voltage signal U1 output by a signal coupling device SCU1 is opposite to the polarity of a voltage signal U2 output by a signal coupling device SCU2 and the polarity of a voltage signal U3 output by a signal coupling device SCU3, the occurrence of a partial discharge source in a power transformer 1 is judged; if the polarity of the voltage signal U2 output by the signal coupling device SCU2 is opposite to the polarity of the voltage signal U1 output by the signal coupling device SCU1 and the polarity of the voltage signal U3 output by the signal coupling device SCU3, it is determined that the partial discharge source is present in the first capacitive device 2; if the polarity of the voltage signal U3 output by the signal coupling device SCU3 is opposite to the polarity of the voltage signal U1 output by the signal coupling device SCU1 and the polarity of the voltage signal U2 output by the signal coupling device SCU2, it is determined that the partial discharge source is present in the first capacitive device 2; if the polarities of the voltage signal U1 output by the signal coupling device SCU1, the voltage signal U2 output by the signal coupling device SCU2, and the voltage signal U3 output by the signal coupling device SCU3 are the same, it is determined that the external disturbance current I1 occurs.

Preferably, as shown in fig. 4, is an embodiment in which the first capacitive device 2 is a bushing.

The bushing comprises a primary conductor 20 and an insulating core body wrapped outside the primary conductor 20, and a capacitor C1, a capacitor C2, a capacitor C3 and a capacitor C4 are all embedded in the insulating core body; the sleeve pipe still includes inlet terminal 26, outlet terminal 21, goes up flange 22, lower flange 23, mounting flange 25, goes up flange 22 and lower flange 23 and sets up respectively at the both ends of insulating core, and mounting flange 25 sets up at insulating core middle part, and the insulating core is located the upside of mounting flange 25 and still overlaps the insulating oversheath that closely crimps, and inlet terminal 26 is connected with primary conductor 20 and is set up in upper flange 22 one end, and outlet terminal 21 is connected with wire 1 and is set up in flange 13 one end down. Preferably, the insulating outer sheath is a silicon rubber umbrella skirt 14, the upper flange 12 is a Jiang military seat, and the lower flange 13 is a pressure-equalizing ball.

The capacitor C1 is composed of a plurality of coaxial capacitor screens which are alternately arranged with the insulating layer and have gradually increased diameters and gradually shortened lengths, and the capacitor C1 plays a core role of voltage division insulation.

Preferably, the capacitor C2 is a tapped capacitor of the capacitor C1, that is, a capacitor tap connected to the penultimate screen (or several penultimate screens) at the end of the capacitor C1, the capacitor C2 is composed of a plurality of capacitor screens at the end of the capacitor C1, and the number of the capacitor screens of the capacitor C2 is greater than or equal to 1. Or the capacitor C2 is a capacitor independent of the capacitor C1, and the capacitor C2 is formed by connecting a group of capacitor screens in parallel outside the outermost capacitor screen of the capacitor C1.

The capacitor C3 is a shielding capacitor, and is formed by winding or laying a series of mutually insulated and mutually overlapped capacitor screens from one end of the upper flange 22 to the grounding end of the mounting flange 25 along the axial direction while manufacturing the capacitor C1, the capacitor screen of the capacitor C3 is wound or laid outside the corresponding capacitor screen of the capacitor C1, and continuously shifts from the wiring terminal of the high-voltage end along the axial direction and is mutually overlapped. Specifically, as shown in fig. 4, the capacitive screen of the capacitor C3 is wound or laid outside the main insulating capacitor C1 from the upper end to the lower end of the insulating core alternately with the insulating layer, adjacent capacitive screens are insulated from each other and are nested with each other, and the multiple capacitive screens of the capacitor C3 are sequentially shifted downward from top to bottom along the axial direction of the primary conductor 20, that is, in two adjacent capacitive screens, the lower end of the capacitive screen located above is located in the capacitive screen below, and the lower end of the capacitive screen located above is nested with the upper end of the capacitive screen located below.

Preferably, the capacitor C4 is a tap capacitor of the capacitor C3 and is composed of a plurality of capacitor screens at the tail end of the capacitor C3, and the number of the capacitor screens of the capacitor C4 is more than or equal to 1. Or the capacitor C4 is a capacitor independent of the capacitor C3, and the capacitor C4 is formed by connecting a group of capacitor screens in parallel, wherein the group of capacitor screens is wound outside the outermost capacitor screen of the capacitor C3.

Note that the innermost capacitive screens of the capacitor C1 and the capacitor C3 are electrically connected to the primary conductor 1 and have the same potential, and the outermost capacitive screens of the capacitor C2 and the capacitor C4 are grounded.

The first capacitive device 2 may also be a Current Transformer (CT), a voltage transformer (PT), a cable termination, a cable middle head, a lightning arrester, etc., and the device having an insulating core with a capacitor voltage-dividing insulating structure may be provided with a capacitor C1, a capacitor C2, a capacitor C3, and a capacitor C4 in the insulating core.

Fig. 1, 4 and 5 show a second embodiment of the partial discharge source positioning system according to the present invention.

In electrical performance, the power transformer 1 can be equivalently regarded as a capacitor, that is, the capacitor is an equivalent capacitor C0 serially connected between the bus and the ground GND, the power transformer 1 is provided with a first capacitive device 2, the first capacitive device 2 is a bushing, a capacitor C1 and a capacitor C2 are arranged in the bushing, a capacitor C1 and a capacitor C2 are sequentially serially connected between the bus and the ground GND, a capacitor C3 and a capacitor C4 are arranged in a second capacitive device 3, the second capacitive device 3 is a lightning arrester, and the capacitor C3 and the capacitor C4 are sequentially serially connected between the bus and the ground GND; the bushing comprises a primary conductor 20 and an insulating core body wrapped outside the primary conductor 20, wherein the primary conductor 20 and the equivalent capacitor CO are sequentially connected between the bus and the ground GND in series; the partial discharge source positioning system comprises a sensor T1, a signal coupling device SCU1, a signal coupling device SCU2, a signal coupling device SCU3 and partial discharge detection equipment, wherein the sensor T1 is a Rogowski coil LS, the Rogowski coil LS is coupled on a primary conductor 20, the output end of the Rogowski coil LS is connected with the signal coupling device SCU1, two ends of a capacitor C2 are respectively connected with the signal coupling device SCU2, two ends of the capacitor C4 are respectively connected with the signal coupling device SCU3, and the signal coupling device SCU1, the signal coupling device SCU2 and the signal coupling device SCU3 are respectively connected with the partial discharge detection equipment.

When the partial discharge source positioning system detects, if the polarity of a voltage signal U1 output by a signal coupling device SCU1 is opposite to the polarity of a voltage signal U2 output by a signal coupling device SCU2 and the polarity of a voltage signal U3 output by a signal coupling device SCU3, the occurrence of a partial discharge source in a power transformer 1 is judged; if the polarity of the voltage signal U2 output by the signal coupling device SCU2 is opposite to the polarity of the voltage signal U1 output by the signal coupling device SCU1 and the polarity of the voltage signal U3 output by the signal coupling device SCU3, it is determined that the partial discharge source is present in the first capacitive device 2; if the polarity of the voltage signal U3 output by the signal coupling device SCU3 is opposite to the polarity of the voltage signal U1 output by the signal coupling device SCU1 and the polarity of the voltage signal U2 output by the signal coupling device SCU2, it is determined that the partial discharge source is present in the second capacitive device 3; if the polarities of the voltage signal U1 output by the signal coupling device SCU1, the voltage signal U2 output by the signal coupling device SCU2, and the voltage signal U3 output by the signal coupling device SCU3 are the same, it is determined that the external disturbance current I1 occurs.

Preferably, as shown in fig. 4, the capacitor C1 and the capacitor C2 are embedded in the insulating core of the bushing, the capacitor C1 is a main insulating capacitor and is composed of a plurality of coaxial capacitor screens which are gradually increased in diameter and gradually shortened in length and are alternately arranged with the insulating layer, the innermost capacitor screen of the capacitor C1 is electrically connected with the primary conductor 20 and has the same potential, and the outermost capacitor screen of the capacitor C2 is grounded.

Preferably, the capacitor C2 is a tapped capacitor of the capacitor C1, or the capacitor C2 is a capacitor independent of the capacitor C1. The capacitor C3 and the capacitor C4 may not be arranged in the sleeve, the capacitor C3 may be arranged as a shielding capacitor according to needs, or the capacitor C3 and the capacitor C4 may be arranged according to other needs.

Preferably, as shown in fig. 5, the lightning arrester includes a valve core body formed by stacking a plurality of valve plates and an insulating core body sleeved outside the valve core body, the capacitor C3 and the capacitor C4 are both embedded in the insulating core body, and the capacitor C3 is formed by a string of mutually insulated and mutually overlapped capacitor screens wound or laid from one end of the insulating core body to the other end.

Preferably, the capacitor C4 is a tap capacitor of the capacitor C3 and is composed of a plurality of capacitor screens at the tail end of the capacitor C3, and the number of the capacitor screens of the capacitor C4 is more than or equal to 1. Alternatively, the capacitor C4 is a capacitor independent of the capacitor C3 and is composed of a group of capacitor plates arranged outside the outermost capacitor screen of the capacitor C3.

Specifically, as shown in fig. 5, an arrester incoming terminal 30 and an arrester base 31 are arranged at two ends of an insulating core of the arrester, the arrester incoming terminal 30 is a high-voltage end, the arrester base 11a is grounded and is a ground end, the insulating core is sleeved with a silicone rubber umbrella skirt sheath 34, a capacitor C3 is formed by a series of mutually insulated and mutually overlapped capacitor screens wound or laid from one end of the insulating core close to the arrester incoming terminal 30 of the high-voltage end to the ground end of the other end, the capacitor screen of the capacitor C3 continuously shifts and mutually overlaps from the arrester incoming terminal 30 to the arrester base 31 along the axial direction of the arrester, the capacitor C3 is a valve plate voltage-dividing capacitor, the innermost capacitor screen of the capacitor C3 is electrically connected and equipotential with the arrester incoming terminal 30, so as to improve the performance of the arrester, and the outermost capacitor screen of the capacitor C4 is grounded.

Preferably, as shown in fig. 5, the arrester further includes a voltage-sharing cover 32 and a pressure spring 36, the voltage-sharing cover 32 is disposed between the arrester incoming line terminal 30 and the insulating core, a silicone rubber shed sheath 34 is tightly sleeved outside the insulating core, one end of the voltage-sharing cover 32 is connected to the arrester incoming line terminal 30, the other end of the voltage-sharing cover is connected to the silicone rubber shed sheath 34, and the pressure spring 36 is disposed between the voltage-sharing cover 32 and the valve plate, and presses the valve plate against the arrester base 31.

Obviously, the first capacitive device 2 may also be a lightning arrester, a capacitor C1 and a capacitor C2 are arranged in the lightning arrester, the second capacitive device 3 is a bushing, and a capacitor C3 and a capacitor C4 are arranged in the bushing, which also can implement the technical solutions of the present invention, and all belong to the protection scope of the present invention.

As shown in fig. 1, 4 and 6, a third embodiment of the partial discharge source positioning system of the present invention is shown.

The present embodiment differs from the second embodiment mainly in the structure of the second capacitive device 3, said second capacitive device 3 still being a lightning arrester, the capacitor C3 and the capacitor C4 being arranged within the lightning arrester.

As shown in fig. 6, the arrester includes a valve plate core body formed by stacking a plurality of valve plates and an insulating core body sleeved outside the valve plate core body, the capacitor C3 and the capacitor C4 are formed by valve plates of the arrester, the capacitor C3 is formed by sequentially stacking a plurality of valve plates, and the capacitor C3 is a valve plate capacitor; the capacitor C4 is composed of at least one valve plate stacked under a plurality of valve plates of the capacitor C3, and the capacitor C3 is connected with the capacitor C4 in series. In fig. 6, the capacitor C4 is composed of a valve plate disposed between the capacitor C3 and the arrester base 31, the valve plate of the capacitor C4 outputs a monitoring signal through a signal line, and the valve plates take the effect of preventing the high transient overvoltage from being damaged and play a role of sampling and monitoring.

Of course, the lightning arrester can be simultaneously provided with a capacitor formed by the valve plates and a capacitor in the insulating core body according to requirements. For example, the first capacitive device 2 of the local discharge source positioning system of the present invention is an arrester, a capacitor C1, a capacitor C2, a capacitor C3, and a capacitor C4 are disposed in the arrester, the capacitor C1 and the capacitor C2 are formed by valve plates (such as capacitors C3 and C4 in embodiment three), and the capacitor C3 and the capacitor C4 are formed by capacitive screens in an insulating core of the arrester (such as capacitors C3 and C4 in embodiment two). It should be noted that the insulating core of the bushing and the lightning arrester according to the present invention is preferably formed by winding an insulating layer and a capacitive screen alternately with a glass filament impregnated with epoxy resin as the insulating layer and a semi-conductive tape or a metal tape as the capacitive screen.

The following is a third embodiment of the partial discharge source localization system of the present invention.

The power transformer 1 can be equivalently regarded as a capacitor in terms of electrical performance, namely, an equivalent capacitor C0 serially connected between a bus and a ground GND, a first capacitive device 2 is arranged on the power transformer 1, the first capacitive device 2 is any one of a bushing, a lightning arrester, a current transformer, a voltage transformer or a cable terminal, a capacitor C3 and a capacitor C4 are external capacitors independent of the power transformer 1 and the first capacitive device 2, and are sequentially serially connected between the bus and the ground GND, and the first capacitive device 2 comprises a capacitor C1 and a capacitor C2 sequentially serially connected between the bus and the ground GND; the partial discharge source positioning system comprises a sensor T1, a signal coupling device SCU1, a signal coupling device SCU2, a signal coupling device SCU3 and partial discharge detection equipment, wherein the sensor T1 is a Rogowski coil LS, the Rogowski coil LS is coupled on a conductor which is connected with a bus and an equivalent capacitor CO, the output end of the Rogowski coil LS is connected with the signal coupling device SCU1, two ends of a capacitor C2 are respectively connected with the signal coupling device SCU2, two ends of the capacitor C4 are respectively connected with the signal coupling device SCU3, and the signal coupling device SCU1, the signal coupling device SCU2 and the signal coupling device SCU3 are respectively connected with the partial discharge detection equipment.

When the partial discharge source positioning system detects, if the polarity of a voltage signal U1 output by a signal coupling device SCU1 is opposite to the polarity of a voltage signal U2 output by a signal coupling device SCU2 and the polarity of a voltage signal U3 output by a signal coupling device SCU3, the occurrence of a partial discharge source in a power transformer 1 is judged; if the polarity of the voltage signal U2 output by the signal coupling device SCU2 is opposite to the polarity of the voltage signal U1 output by the signal coupling device SCU1 and the polarity of the voltage signal U3 output by the signal coupling device SCU3, it is determined that the partial discharge source is present in the first capacitive device 2; if the polarities of the voltage signal U1 output by the signal coupling device SCU1, the voltage signal U2 output by the signal coupling device SCU2, and the voltage signal U3 output by the signal coupling device SCU3 are the same, it is determined that the external disturbance current I1 occurs.

Fig. 7 shows a first embodiment of the partial discharge detection apparatus according to the present invention.

The partial discharge source detection equipment comprises a signal conditioning unit, a partial discharge signal identification unit, a signal sampling and processing unit, a display system and a communication unit, wherein the signal conditioning unit is respectively connected with a signal coupling device SCU1, a signal coupling device SCU2 and a signal coupling device SCU3, the partial discharge signal identification unit is connected with the signal conditioning unit, the signal sampling and processing unit is connected with the partial discharge signal identification unit, and the display system and the communication unit are respectively connected with the signal sampling and processing unit.

The signal conditioning unit can amplify, filter and the like the voltage signal U1 output by the signal coupling device SCU1, the voltage signal U2 output by the signal coupling device and the voltage signal U3 output by the signal coupling device SCU 3; the partial discharge signal identification unit realizes the positioning of a partial discharge source and the detection of the partial discharge sources of different devices through a hardware circuit; the signal sampling and processing unit is used for displaying the processing result of the partial discharge signal identification unit through the display system and sending the processing result to an upper computer and/or a user side (such as a smart phone, a tablet personal computer and the like) through the communication unit, so that the user can conveniently monitor the running state of the transformer in real time, and timely handle the transformer when a partial discharge source occurs, and the reliable and stable running of the power transformer is ensured.

Fig. 8 shows a second embodiment of the partial discharge detection apparatus according to the present invention.

The present embodiment is different from the above-described embodiments in that the partial discharge source detecting device of the present embodiment is not provided with the partial discharge signal identifying unit.

The signal conditioning unit of the present embodiment has the same function as the signal conditioning unit of the above embodiment; the signal sampling and processing unit of this embodiment realizes the location of the partial discharge source and the detection of the partial discharge source of different equipment through the algorithm to show the processing result through display system, and send to host computer and/or user (for example smart mobile phone, panel computer etc.) through the communication unit, the user of being convenient for monitors the running state of transformer in real time to and when the partial discharge source takes place, in time deal with, guarantee the reliable and stable operation of power transformer. The signal sampling and processing unit comprises a processor, and the processor can adopt a single chip microcomputer or other processors capable of meeting application requirements.

It should be noted that, as shown in fig. 7 and 8, ports 1-N (where N is an integer greater than or equal to 3) of the signal conditioning unit are used to connect to a signal coupling device, and the signal coupling device SU1/SU2/SU3 of the present invention is respectively connected to three ports, however, the partial discharge source positioning system of the present invention is not limited to the partial discharge source positioning for three devices, namely, a power transformer, a bushing, and a lightning arrester, but can also be used for the partial discharge source positioning for more devices.

Fig. 3 is a schematic circuit diagram of the partial discharge source positioning system according to the present invention.

The power transformer 1 is connected in series between a bus and a ground GND as an equivalent capacitor C0, a capacitor C1 and a capacitor C2 are connected in series between the bus and the ground GND, a capacitor C3 and a capacitor C4 are connected in series between the bus and the ground GND, a sensor T1 is coupled to a conductor connecting the bus and the equivalent capacitor CO, an output end of the sensor T1 is connected to a signal coupling device SCU1, two ends of the capacitor C2 are connected to a signal coupling device SCU2, two ends of the capacitor C4 are connected to a signal coupling device SCU3, and the signal coupling device SCU1, the signal coupling device SCU2 and the signal coupling device SCU3 are connected to a partial discharge positioning device (not shown in fig. 3). The partial discharge source positioning system of the invention has the following four situations:

in case one, when the external disturbance current I1 occurs, the external disturbance current I1 flows into each branch from the bus, so that the polarities of the voltage signal U1 output by the signal coupling device SCU1, the voltage signal U2 output by the signal coupling device SCU2, and the voltage signal U3 output by the signal coupling device SCU3 are the same.

In the second situation, when partial discharge occurs inside the transformer, that is, when a partial discharge source occurs in the equivalent capacitor C0, a pulse current I0 flowing from the equivalent capacitor C0 to the bus is generated, if the current direction of I0 flows from ground to the bus, assuming that the current direction is negative, the sensor T1 senses the pulse current I0 and converts the pulse current I0 into a voltage signal U1 through the signal coupling device SCU1, and the polarity of the voltage signal U1 is the same as the polarity of the pulse current I0 and is negative; the pulse current I1 causes the signal coupling device SCU2 to output a voltage signal U2, and causes the signal coupling device SCU3 to output a voltage signal U3, wherein the polarity of the voltage signal U2 and the voltage signal U3 is opposite to the polarity of the voltage signal U1, and is positive.

Similarly, when the partial discharge source is present in the capacitor C1, the polarity of the voltage signal U2 output by the signal coupling device SCU2 is opposite to the polarity of the voltage signal U1 output by the signal coupling device SCU1 and the polarity of the voltage signal U3 output by the signal coupling device SCU 3.

In the same way, when the partial discharge source is present in the capacitor C3, the polarity of the voltage signal U3 output by the signal coupling device SCU3 is opposite to the polarity of the voltage signal U1 output by the signal coupling device SCU1 and the polarity of the voltage signal U2 output by the signal coupling device SCU 2.

In other words, the partial discharge source positioning system of the present invention is in the case one, which indicates that no partial discharge source exists inside the power transformer 1, the bushing and/or the lightning arrester, but an external interference current I1 occurs; when the partial discharge source positioning system is in the second situation, the partial discharge source exists in the power transformer 1; the capacitors C1, C2, C3 and C4 are all arranged in the sleeve, and the partial discharge source positioning system is in a third situation or a fourth situation, which indicates that a partial discharge source exists in the sleeve; the capacitor C1 and the capacitor C2 are arranged in the sleeve, the capacitor C3 and the capacitor C4 are arranged in the arrester, when the partial discharge source positioning system is in a third situation, the partial discharge source exists in the sleeve, and when the partial discharge source positioning system is in a fourth situation, the partial discharge source exists in the arrester.

The partial discharge positioning device comprises a processor, wherein the processor receives collected voltage signals U1 of the power transformer, and voltage signals U2 and U3 collected by capacitive devices connected with the power transformer, the voltage signals U2 and U3 are from the same first capacitive device 2, or the voltage signals U2 and U3 are from the first capacitive device 2 and the second capacitive device 3 respectively.

The partial discharge positioning device can judge whether a partial discharge source exists through the collected voltage signal U2, and further can distinguish whether the partial discharge source comes from a power transformer, the first capacitive device 2, the second capacitive device 3 or external interference (external interference current I1) through the polarity judgment of the voltage signal U1, the voltage signal U2 and the voltage signal U3, so that the partial discharge source is positioned.

The processor of the partial discharge positioning device executes the following method:

receiving a collected voltage signal U1 of the power transformer, and receiving a voltage signal U2 and a voltage signal U3 collected by a capacitive device connected with the power transformer;

when the partial discharge source is detected, if the polarity of the voltage signal U1 is opposite to the polarities of the voltage signal U2 and the voltage signal U3, judging that the partial discharge source appears in the power transformer 1; if the polarity of the voltage signal U2 is opposite to the polarities of the voltage signal U1 and the voltage signal U3, it is determined that the partial discharge source occurs in the capacitive device outputting the voltage signal U2, i.e., the first capacitive device 2; if the polarities of the voltage signal U1, the voltage signal U2 and the voltage signal U3 are the same, it is determined that external interference (external interference current I1) occurs, and no partial discharge source exists in the power transformer and the capacitive device.

If the polarity of the voltage signal U3 is opposite to the polarity of the voltage signal U1 and the voltage signal U2, it is determined that a partial discharge source is present in the capacitive device outputting the voltage signal U3. When the voltage signal U2 and the voltage signal U3 both come from the same first capacitive device 2, and the polarity of the voltage signal U3 is opposite to the polarity of the voltage signal U1 and the voltage signal U2, it is determined that a partial discharge source occurs in the first capacitive device 2; when the voltage signal U2 and the voltage signal U3 are respectively from the first capacitive device 2 and the second capacitive device 3, if the polarity of the voltage signal U3 is opposite to the polarity of the voltage signal U1 and the voltage signal U2, it is determined that the partial discharge source is present in the second capacitive device 3.

The processor of the partial discharge positioning device may adopt an ARM chip (or other processors capable of meeting application requirements), and the partial discharge positioning device further includes a storage unit, a communication unit, and a power supply unit. The partial discharge positioning device can further integrate a signal coupling device SCU1, a signal coupling device SCU2 and a signal coupling device SCU3, wherein an input end of the signal coupling device SCU1 is used for being connected with a signal acquisition unit (rogowski coil) of the power transformer, an input end of the signal coupling device SCU2 is used for being connected with a first capacitive device connected with the power transformer, an input end of the signal coupling device SCU3 is used for being connected with a first capacitive device connected with the power transformer or an input end of the signal coupling device SCU3 is used for being connected with a second capacitive device connected with the power transformer.

The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.

Claims (10)

1. The partial discharge source positioning system is characterized by comprising partial discharge detection equipment and first capacitive equipment (2) connected with a power transformer (1), wherein the first capacitive equipment (2) comprises a capacitor C1 and a capacitor C2 which are arranged in the first capacitive equipment and sequentially connected in series between a bus and a ground GND (ground), and the partial discharge source positioning system further comprises a capacitor C3 and a capacitor C4 which are sequentially connected in series between the bus and the ground GND;

the sensor T1 is coupled on a conductor which connects the power transformer (1) and the bus, the output end of the sensor T1 is connected with the partial discharge detection equipment to output a voltage signal U1, the two ends of the capacitor C2 are respectively connected with the partial discharge detection equipment to output a voltage signal U2, and the two ends of the capacitor C4 are respectively connected with the partial discharge detection equipment to output a voltage signal U3; the partial discharge detection equipment identifies the position of an external interference or a positioning partial discharge source according to the polarities of the voltage signal U1, the voltage signal U2 and the voltage signal U3.

2. The partial discharge source localization system according to claim 1, wherein: the partial discharge source positioning system further comprises a signal coupling device SCU1, a signal coupling device SCU2 and a signal coupling device SCU3, the output end of the sensor T1 is connected with the signal coupling device SCU1, two ends of a capacitor C2 are respectively connected with the signal coupling device SCU2, two ends of a capacitor C4 are respectively connected with the signal coupling device SCU3, the signal coupling device SCU1, the signal coupling device SCU2 and the signal coupling device SCU3 are respectively connected with partial discharge detection equipment and are respectively used for collecting a voltage signal U1, a voltage signal U2 and a voltage signal U3;

the signal coupling device SCU1, the signal coupling device SCU2, the signal coupling device SCU3 and the partial discharge detection equipment are mutually independent equipment; alternatively, the signal coupling device SCU1, the signal coupling device SCU2, the signal coupling device SC3 and the partial discharge source detecting device are an integrated device.

3. The partial discharge source localization system according to claim 1 or 2, wherein: the capacitor C3 and the capacitor C4 are also arranged in the first capacitive device (2).

4. The partial discharge source localization system according to claim 1 or 2, wherein: the capacitor C3 and the capacitor C4 are arranged in the second capacitive device (3).

5. The partial discharge source localization system according to claim 3, wherein: the first capacitive equipment (2) comprises an insulating core body with a capacitance voltage-dividing insulating structure, a plurality of capacitance screens alternately arranged with an insulating layer are embedded in the insulating core body, and the capacitance C1, the capacitance C2, the capacitance C3 and the capacitance C4 are all embedded in the insulating core body and are formed by the plurality of capacitance screens embedded in the insulating core body.

6. The partial discharge source localization system according to claim 5, wherein: the first capacitive equipment (2) is a sleeve, a lightning arrester, a current transformer, a voltage transformer or a cable terminal.

7. The partial discharge source localization system according to claim 3, wherein: the first capacitive device (2) is a bushing, the bushing further comprises a primary conductor (20) and an insulating core wrapped outside the primary conductor (20), the primary conductor (20) is connected with the power transformer 1, and the sensor T1 is coupled on the primary conductor (20); the capacitor C1, the capacitor C2, the capacitor C3 and the capacitor C4 are embedded in the insulating core body, an upper flange (22) and a lower flange (23) are respectively arranged at two ends of the insulating core body, and a mounting flange (15) is arranged in the middle of the insulating core body; the capacitor C1 is composed of a plurality of coaxial capacitor screens which are alternately arranged with insulating layers and have gradually increased diameters and gradually shortened lengths, the capacitor C2 is a tap capacitor of the capacitor C1, or the capacitor C2 is composed of a group of capacitor screens which are arranged outside the capacitor screen at the outermost side of the capacitor C1 and are connected in parallel; the capacitor C3 is composed of a group of mutually insulated and mutually overlapped capacitor screens arranged outside the capacitor screen of the corresponding capacitor C1 from one end of the upper flange (12) to the grounding end of the mounting flange (15) along the axial direction, the capacitor C4 is a tap capacitor of the capacitor C3, or the capacitor C4 is composed of a group of capacitor screens arranged outside the outermost capacitor screen of the capacitor C3 in parallel.

8. The partial discharge source localization system according to claim 4, wherein: the first capacitive equipment (2) and the second capacitive equipment (3) are respectively any two of a sleeve, a lightning arrester, a current transformer, a voltage transformer, a cable terminal or a cable middle head;

the first capacitive equipment (2) is a sleeve, and the second capacitive equipment (3) is a lightning arrester;

the bushing further comprises a primary conductor (20) and an insulating core wrapped outside the primary conductor (20), the primary conductor (20) is connected with the power transformer (1), and the sensor T1 is coupled on the primary conductor (20); the capacitor C1 and the capacitor C2 are embedded in the insulating core, the capacitor C1 is a main insulating capacitor and consists of a plurality of coaxial capacitor screens which are gradually increased in diameter and gradually shortened in length and are alternately arranged with the insulating layers; the capacitor C2 is a tap capacitor of the capacitor C1, or the capacitor C2 is formed by connecting a group of capacitor screens in parallel outside the capacitor screen at the outermost side of the capacitor C1;

the second capacitive equipment (3) is an arrester, the arrester comprises a valve plate core body formed by stacking a plurality of valve plates and an insulating core body sleeved outside the valve plate core body, the capacitor C3 and the capacitor C4 are formed by valve plates of the arrester, the capacitor C3 is formed by sequentially stacking a plurality of valve plates, and the capacitor C4 is formed by at least one valve plate stacked below the plurality of valve plates of the capacitor C3;

the second capacitive equipment (3) is an arrester, the arrester comprises a valve plate core body formed by stacking a plurality of valve plates and an insulating core body sleeved outside the valve plate core body, a capacitor C3 and a capacitor C4 are embedded in the insulating core body, and the capacitor C3 is composed of a series of mutually insulated and mutually overlapped capacitor screens arranged from one end of the insulating core body to the other end of the insulating core body; the capacitor C4 is a tap capacitor of the capacitor C3, or the capacitor C4 is formed by connecting a group of capacitor screens in parallel outside the outermost capacitor screen of the capacitor C3;

if the polarity of the voltage signal U1 is opposite to the polarities of the voltage signal U2 and the voltage signal U3, judging that an partial discharge source exists in the power transformer (1); if the polarity of the voltage signal U2 is opposite to the polarities of the voltage signal U1 and the voltage signal U3, judging that a partial discharge source exists in the first capacitive equipment (2); if the polarities of the voltage signal U1, the voltage signal U2 and the voltage signal U3 are the same, judging that external interference current occurs;

the capacitor C3 and the capacitor C4 are also arranged in the first capacitive device (2); if the polarity of the voltage signal U3 is opposite to the polarities of the voltage signal U1 and the voltage signal U2, judging that a partial discharge source exists in the first capacitive equipment (2);

the capacitor C3 and the capacitor C4 are arranged in the second capacitive device (3); if the polarity of the voltage signal U3 is opposite to the polarity of the voltage signal U1 and the voltage signal U2, the occurrence of the partial discharge source in the second capacitive device (3) is judged.

9. A partial discharge source positioning method is characterized in that:

receiving a collected voltage signal U1 of the power transformer, and receiving a voltage signal U2 and a voltage signal U3 collected by a capacitive device connected with the power transformer;

when the partial discharge source is detected, if the polarity of the voltage signal U1 is opposite to the polarities of the voltage signal U2 and the voltage signal U3, judging that the partial discharge source exists in the power transformer;

if the polarity of the voltage signal U2 is opposite to the polarities of the voltage signal U1 and the voltage signal U3, judging that a partial discharge source exists in the capacitive equipment outputting the voltage signal U2;

if the polarity of the voltage signal U3 is opposite to the polarities of the voltage signal U1 and the voltage signal U2, judging that a partial discharge source exists in the capacitive equipment outputting the voltage signal U3;

if the polarities of the voltage signal U1, the voltage signal U2, and the voltage signal U3 are the same, it is determined as an external disturbance.

10. An partial discharge detection device comprising a processor, characterized in that: the processor performs the partial discharge source localization method of claim 9.

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