Capacitor and method for measuring dielectric loss through forward and reverse connection

Abstract

The invention discloses a capacitor and a method for measuring dielectric loss through forward and reverse connection simultaneously. The capacitor comprises a capacitor body arranged in a shell. Capacitor leading-out ends electrically connected with the capacitor are located at the two ends of the shell. The capacitor comprises a lower-end shielding layer and an upper-end shielding layer which are arranged at two ends of the supporting layer; a lower end electrode copper column and an upper end electrode copper column are respectively arranged in the lower end shielding layer and the upper end shielding layer; the lower end electrode copper column is electrically connected with the lower end capacitor electrode plate; the upper end electrode copper column is electrically connected with the upper end capacitor electrode plate; the lower end capacitor electrode plate wraps the upper end capacitor electrode plate; an electrode core is formed in the middle of the upper-end capacitor electrode plate; when a positive connection method is adopted to measure the dielectric loss of the end screen of the bushing, the low-voltage end of the capacitor collects a current signal. Test time is saved, test wiring times, test times and power-on and power-off times are reduced, and test safety is improved; the number of used capacitors is reduced, cost is reduced, efficiency is improved, the size and weight of carried detection equipment are reduced, and operation of testers is facilitated.

Description

Technical Field

[0001] The invention belongs to the technical field of power equipment measurement, and relates to a capacitor and a method for simultaneously measuring dielectric loss by positive and negative connection. Background Art

[0002] Measuring dielectric loss is an effective means to determine the insulation status of power equipment such as power transformers, capacitors, and high-voltage bushings. It is a major inspection item for power transformer handover and preventive testing. Measuring dielectric loss can reflect defects such as overall insulation moisture, impregnation dirt, and deterioration.

[0003] At present, the capacitors for measuring dielectric loss generally only have one terminal for collecting current signals, and only one end of the internal capacitor is led out, so only one of the positive connection or reverse connection method can be used, and the positive connection method and reverse connection method cannot be used at the same time. When measuring the dielectric loss of the transformer, the dielectric loss of the transformer winding shell is measured by the reverse connection method, and the dielectric loss of the bushing end screen is measured by the positive connection method. At present, two standard capacitors are required to measure the dielectric loss of the winding shell and the dielectric loss of the transformer bushing end screen at the same time. The capacitors are large in size and heavy in weight, which is inconvenient to carry. When testing separately, one capacitor is used, but the test process requires repeated disconnection and wiring, the test time is long, the number of power on and off increases, and the test risk increases. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a capacitor and method for measuring dielectric loss by both positive and negative connection. One end is used as a high-voltage input end. When the positive connection method is used to measure the dielectric loss of the end screen of the bushing, the low-voltage end of the capacitor collects current signals. When the reverse connection method is used to measure the dielectric loss of the outer shell, the low-voltage end is grounded and the high-voltage end collects current signals.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a capacitor used for both positive and negative connection to measure dielectric loss, which includes a capacitor arranged in a shell; the capacitor lead-out terminals electrically connected to the capacitor are located at both ends of the shell; the capacitor includes a lower shielding layer and an upper shielding layer arranged at both ends of the supporting layer; the lower shielding layer and the upper shielding layer are respectively provided with a lower electrode copper column and an upper electrode copper column; the lower electrode copper column is electrically connected to the lower capacitor electrode plate; the upper electrode copper column is electrically connected to the upper capacitor electrode plate; the lower capacitor electrode plate wraps the upper capacitor electrode plate; and an electrode core is formed in the middle of the upper capacitor electrode plate.

[0006] The end of the shell is provided with a plurality of mounting holes, and the fasteners pass through the mounting holes and are connected to the capacitor lead-out terminals.

[0007] The supporting layer is epoxy resin.

[0008] The lower shielding layer and the upper shielding layer are made of aluminum alloy.

[0009] The lower shielding layer and the upper shielding layer are both connected to the supporting layer by threads or by glue injection.

[0010] The lower end shielding layer and the lower end electrode copper column and the upper end shielding layer and the upper end electrode copper column are connected by glue pouring.

[0011] The lower electrode copper column and the lower capacitor electrode plate, and the upper electrode copper column and the upper capacitor electrode plate are electrically connected via wires.

[0012] The lower end electrode copper column and the lower end capacitor electrode plate are threadedly connected by a lower end insulating sleeve, and the lower end capacitor electrode plate is fixed on the lower end electrode copper column.

[0013] The upper electrode copper column and the upper capacitor electrode plate are threadedly connected by an upper insulating sleeve to fix the upper capacitor electrode plate on the upper electrode copper column.

[0014] The method for connecting and testing a capacitor for measuring dielectric loss by connecting both positive and negative connections as described above comprises the following steps: S1, when the positive connection method is used to measure the dielectric loss of the transformer bushing end screen, the instrument and the upper and lower ends of the capacitor are connected, and a high voltage of 10000V is applied to the high voltage end of the capacitor. The high voltage line and the shielding line at the high voltage end are short-circuited by the relay between them, and the low voltage end test line and the shielding line are disconnected by the relay between them. The current signal I1 is collected at the low voltage end test line end to calculate the dielectric loss value and capacitance value; S2, when the reverse connection method is used to measure the dielectric loss of the transformer winding to the casing, the instrument and the upper and lower ends of the capacitor are connected, and a high voltage of 10,000 V is applied to the high voltage end of the capacitor. The high voltage line and the shielding line at the high voltage end are disconnected through the relay between them, and the low voltage end test line and the shielding line are short-circuited through the relay between them. The current signal I2 is collected at the high voltage test line end to calculate the dielectric loss value and capacitance value.

[0015] The main beneficial effects of the present invention are: Only one capacitor is needed to complete the measurement of the transformer bushing end screen and winding shell dielectric loss in both positive and reverse connection methods. It is simple and convenient to use. It can reduce the number of capacitors used, reduce the volume and weight of the test equipment, reduce costs and increase efficiency, and facilitate the operation of test personnel.

[0016] Save test time, reduce test wiring times, test times, power on and off times, and improve test safety.

[0017] The insulation design inside the capacitor is simpler, the size and weight of the equipment will be reduced, and the internal structure of the capacitor adopts threaded connection and glue filling connection, which improves the insulation effect and makes the structure more compact, thereby improving the safety of the test and avoiding safety hazards. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0019] Figure 1 It is a structural schematic diagram of the present invention.

[0020] Figure 2 It is a schematic diagram of the internal structure of the capacitor of the present invention.

[0021] Figure 3 This is the wiring diagram of the capacitor circuit for measuring dielectric loss using the positive connection method of the present invention.

[0022] Figure 4 This is the wiring diagram of the capacitor circuit for measuring dielectric loss using the reverse connection method of the present invention.

[0023] In the figure: shell 1; mounting hole 2; capacitor lead-out terminal 3; supporting layer 4; lower end shielding layer 5; lower end electrode copper column 6; lower end insulating sleeve 7; lower end capacitor electrode plate 8; electrode core 9; upper end capacitor electrode plate 10; upper end insulating sleeve 11; upper end shielding layer 12; upper end electrode copper column 13. DETAILED DESCRIPTION

[0024] like Figure 1~Figure 4 A capacitor for measuring dielectric loss in both positive and negative connection is disclosed, which includes a capacitor arranged in a shell 1; capacitor lead-out terminals 3 electrically connected to the capacitor are located at both ends of the shell 1; the capacitor includes a lower shielding layer 5 and an upper shielding layer 12 arranged at both ends of a support layer 4; a lower electrode copper column 6 and an upper electrode copper column 13 are respectively arranged in the lower shielding layer 5 and the upper shielding layer 12; the lower electrode copper column 6 is electrically connected to a lower capacitor electrode plate 8; the upper electrode copper column 13 is electrically connected to an upper capacitor electrode plate 10; the lower capacitor electrode plate 8 wraps the upper capacitor electrode plate 10; and an electrode core 9 is formed in the middle of the upper capacitor electrode plate 10.

[0025] Preferably, one end of the capacitor is used as the high-voltage input end. When the dielectric loss of the bushing end screen is measured by the positive connection method, the low-voltage end of the capacitor collects the current signal. When the dielectric loss shell is measured by the reverse connection method, the low-voltage end is grounded and the high-voltage end collects the current signal.

[0026] In a preferred solution, the end of the housing 1 is provided with a plurality of mounting holes 2, and the fasteners pass through the mounting holes 2 and are connected to the capacitor lead-out terminals 3.

[0027] Preferably, both ends of the housing 1 have terminals for current sampling, both ends can be led out, and both ends can be connected in a positive or reverse connection manner, and both methods can measure dielectric loss. Only one capacitor is needed to complete the positive and reverse connection methods to simultaneously measure the dielectric loss of the transformer bushing end screen and the winding housing, and the operation is simple and convenient. It can reduce the number of capacitors used, reduce the volume and weight of the carried detection equipment, reduce costs and increase efficiency, and facilitate the operation of test personnel.

[0028] In a preferred embodiment, the support layer 4 is epoxy resin.

[0029] Preferably, the supporting layer 4 is made of epoxy resin to support the entire capacitor and provide good insulation effect.

[0030] In a preferred solution, the lower shielding layer 5 and the upper shielding layer 12 are made of aluminum alloy.

[0031] In a preferred solution, the lower shielding layer 5 and the upper shielding layer 12 are both connected to the supporting layer 4 by threads or by glue injection.

[0032] Preferably, the lower shielding layer 5 , the upper shielding layer 12 and the supporting layer 4 are connected by glue potting to achieve insulation and sealing effects.

[0033] In a preferred solution, the lower shielding layer 5 and the lower electrode copper pillar 6 as well as the upper shielding layer 12 and the upper electrode copper pillar 13 are connected by glue potting.

[0034] Preferably, the glue-filling connection is used to achieve insulation and sealing effects between the lower shielding layer 5 and the lower electrode copper pillar 6 and between the upper shielding layer 12 and the upper electrode copper pillar 13 .

[0035] In a preferred embodiment, the lower electrode copper column 6 and the lower capacitor electrode plate 8 as well as the upper electrode copper column 13 and the upper capacitor electrode plate 10 are electrically connected via wires.

[0036] In a preferred solution, the lower electrode copper column 6 and the lower capacitor electrode plate 8 are threadedly connected by a lower insulating sleeve 7 to fix the lower capacitor electrode plate 8 on the lower electrode copper column 6 .

[0037] In a preferred solution, the upper electrode copper column 13 and the upper capacitor electrode plate 10 are threadedly connected by an upper insulating sleeve 11 to fix the upper capacitor electrode plate 10 on the upper electrode copper column 13 .

[0038] In a preferred embodiment, the method for measuring the dielectric loss of a capacitor for both positive and negative connection as described above comprises the following steps: S1, when the positive connection method is used to measure the dielectric loss of the transformer bushing end screen, the instrument and the upper and lower ends of the capacitor are connected, and a high voltage of 10000V is applied to the high voltage end of the capacitor. The high voltage line and the shielding line at the high voltage end are short-circuited by the relay between them, and the low voltage end test line and the shielding line are disconnected by the relay between them. The current signal I1 is collected at the low voltage end test line end to calculate the dielectric loss value and capacitance value; S2, when the reverse connection method is used to measure the dielectric loss of the transformer winding to the casing, the instrument and the upper and lower ends of the capacitor are connected, and a high voltage of 10,000 V is applied to the high voltage end of the capacitor. The high voltage line and the shielding line at the high voltage end are disconnected through the relay between them, and the ground potential end test line and the shielding line are short-circuited through the relay control between them, and the current signal I2 is collected at the high voltage test line end to calculate the dielectric loss value and capacitance value.

[0039] In the above method, the positive connection method and the reverse connection method are two different measurement methods. The reverse connection method is used to measure the dielectric loss of the transformer winding to the shell, and the positive connection method is used to measure the dielectric loss of the bushing end screen. When testing, the positive connection method is to connect one end of the capacitor to high voltage and the other end to current signal sampling; the reverse connection method is to connect one end to high voltage and the other end to current signal sampling, and the shell is grounded. The present invention can be used for the automated measurement of the dielectric loss of power transformers. Only one capacitor is needed to measure the dielectric loss of the transformer winding to the shell and the dielectric loss of the bushing end screen. Compared with traditional capacitors that can only be measured by the positive connection method or the reverse connection method, it saves test time, reduces the number of test wiring, the number of tests, and the number of power on and off, and improves test safety; reduces the number of capacitors used, reduces costs and increases efficiency, reduces the volume and weight of the carried detection equipment, and is convenient for test personnel to operate.

[0040] The above-mentioned embodiments are only preferred technical solutions of the present invention and should not be regarded as limitations of the present invention. The embodiments and features in the embodiments of the present application can be arbitrarily combined with each other without conflict. The protection scope of the present invention shall be the technical solutions recorded in the claims, including the equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A capacitor used for both positive and negative connection to measure dielectric loss, characterized by: The invention comprises a capacitor arranged in a shell (1); capacitor lead-out terminals (3) electrically connected to the capacitor are located at two ends of the shell (1); the capacitor comprises a lower shielding layer (5) and an upper shielding layer (12) arranged at two ends of a support layer (4); a lower electrode copper column (6) and an upper electrode copper column (13) are respectively arranged in the lower shielding layer (5) and the upper shielding layer (12); the lower electrode copper column (6) is electrically connected to a lower capacitor electrode plate (8); the upper electrode copper column (13) is electrically connected to an upper capacitor electrode plate (10); the lower capacitor electrode plate (8) wraps the upper capacitor electrode plate (10); and an electrode core (9) is formed in the middle of the upper capacitor electrode plate (10).

2. The capacitor for measuring dielectric loss in both forward and reverse connection according to claim 1 is characterized in that: The end of the housing (1) is provided with a plurality of mounting holes (2), and the fasteners pass through the mounting holes (2) and are connected to the capacitor lead-out terminals (3).

3. The capacitor for measuring dielectric loss in both forward and reverse connection according to claim 1 is characterized in that: The support layer (4) is epoxy resin.

4. The capacitor for measuring dielectric loss in both forward and reverse connection according to claim 1 is characterized in that: The lower shielding layer (5) and the upper shielding layer (12) are made of aluminum alloy.

5. The capacitor for measuring dielectric loss in both forward and reverse connection according to claim 1 is characterized in that: The lower shielding layer (5) and the upper shielding layer (12) are both threadedly connected or glue-filled connected to the support layer (4).

6. The capacitor for measuring dielectric loss in both forward and reverse connection according to claim 1, characterized in that: The lower end shielding layer (5) and the lower end electrode copper column (6) as well as the upper end shielding layer (12) and the upper end electrode copper column (13) are connected by glue pouring.

7. The capacitor for measuring dielectric loss in both forward and reverse connection according to claim 1 is characterized in that: The lower electrode copper column (6) and the lower capacitor electrode plate (8) as well as the upper electrode copper column (13) and the upper capacitor electrode plate (10) are electrically connected via wires.

8. The capacitor for measuring dielectric loss in both forward and reverse connection according to claim 1, characterized in that: The lower end electrode copper column (6) and the lower end capacitor electrode plate (8) are threadedly connected by a lower end insulating sleeve (7), so that the lower end capacitor electrode plate (8) is fixed on the lower end electrode copper column (6).

9. The capacitor for measuring dielectric loss in both forward and reverse connection according to claim 1, characterized in that: The upper electrode copper column (13) and the upper capacitor electrode plate (10) are threadedly connected by an upper insulating sleeve (11), and the upper capacitor electrode plate (10) is fixed to the upper electrode copper column (13).

10. The method for measuring the dielectric loss of a capacitor for both positive and negative connection according to any one of claims 1 to 9, characterized in that: The steps include: S1, when the positive connection method is used to measure the dielectric loss of the transformer bushing end screen, the instrument and the upper and lower ends of the capacitor are connected, and a high voltage of 10000V is applied to the high voltage end of the capacitor. The high voltage line and the shielding line at the high voltage end are short-circuited by the relay between them, and the low voltage end test line and the shielding line are disconnected by the relay between them. The current signal I1 is collected at the low voltage end test line end to calculate the dielectric loss value and capacitance value; S2, when the reverse connection method is used to measure the dielectric loss of the transformer winding to the casing, the instrument and the upper and lower ends of the capacitor are connected, and a high voltage of 10,000 V is applied to the high voltage end of the capacitor. The high voltage line and the shielding line at the high voltage end are disconnected through the relay between them, and the low voltage end test line and the shielding line are short-circuited through the relay between them. The current signal I2 is collected at the high voltage test line end to calculate the dielectric loss value and capacitance value.

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