Distributed capacitive equipment on-line monitoring device applied to GIS

Abstract

The utility model discloses a distributed capacitive equipment on-line monitoring device applied to a GIS (Gas Insulated Switchgear). The distributed capacitive equipment on-line monitoring device comprises a bus voltage monitoring device and a capacitive equipment monitoring device, the bus voltage monitoring device comprises three voltage transformers which are used for monitoring voltage amplitudes and phases of A, B and C three-phase voltages. The capacitive equipment monitoring device comprises three zero-flux current transformers which are used for monitoring numerical values and phases of total currents of three capacitive equipment. The system also comprises a commercial power voltage transformer which is used for monitoring the voltage amplitude and phase of the commercial power. The system also comprises an RS485 communication module. The capacitive equipment monitoring device mainly collects parameters such as related current and phase of capacitive equipment, bus voltage collects parameters such as voltage amplitude and phase of a three-phase bus, and functions such as data interaction, data transmission, signal synchronization, collection and calculation can be realized by the capacitive equipment monitoring device and the bus voltage through only one communication bus; a traditional method of connecting multiple bus signals to capacitive equipment is abandoned.

Description

Technical Field

[0001] This utility model relates to an online monitoring device for capacitive equipment, specifically a distributed online monitoring device for capacitive equipment applied to GIS. Background Technology

[0002] Capacitive equipment (such as high-voltage bushings, capacitive voltage transformers, and coupling capacitors) is an indispensable component of power systems, undertaking key functions such as voltage conversion, signal coupling, and insulation protection, accounting for 40%-50% of the total equipment in substations. Its insulation performance directly affects the safety and reliability of the power grid. However, during long-term operation, capacitive equipment is susceptible to factors such as temperature, humidity, and pollution, leading to insulation aging or breakdown, which may cause major accidents. To ensure the safe operation of electrical equipment in power systems, some preventative testing items have been gradually established based on long-term operational experience and experimental research. However, the regulations require regular power outages for preventative insulation testing and maintenance of electrical equipment, which is somewhat unreasonable, resulting in a waste of manpower and resources, and also failing to detect latent insulation faults in electrical equipment in a timely manner.

[0003] Existing technical solutions and their disadvantages:

[0004] 1. Technical limitations: Detection accuracy and dynamic failure

[0005] The disconnect between offline testing and real-world operating conditions is a problem. Traditional methods require testing to be performed when the equipment is powered off (such as measuring the dielectric loss tangent tanδ and insulation resistance). However, in actual operation, the equipment is subjected to complex conditions such as power frequency voltage, harmonic superposition, and temperature fluctuations.

[0006] Insufficient sensitivity and risk of missed detection;

[0007] Early defects are difficult to detect: Traditional methods have limited ability to identify minute defects (such as microcracks in the insulating medium and localized moisture).

[0008] Dynamic failures cannot be monitored: Sudden faults (such as instantaneous breakdown caused by lightning overvoltage) cannot be detected by periodic testing, while online monitoring can capture transient signals (such as sudden changes in leakage current) in real time.

[0009] 2. Economic drawbacks: High costs and inefficient operation and maintenance

[0010] Power outages are costly, and traditional testing methods require power outages, resulting in direct economic losses.

[0011] Waste of human and equipment resources;

[0012] 3. Safety and operational risks

[0013] Human error is a potential hazard. Traditional testing relies on manual operation, which can easily lead to data distortion or even short circuits due to wiring errors or improper instrument parameter settings (such as incorrect balance adjustment in the bridge method).

[0014] The risk of secondary damage to equipment: Frequent disassembly and reassembly of equipment (such as disconnecting the bushing end screen) may damage the sealing structure and accelerate insulation aging. For example, a 500kV substation experienced seal failure due to repeated disassembly of the bushing end screen, leading to an internal moisture-induced fault.

[0015] 4. Lack of real-time performance: The inability to provide continuous status trend curves leads to delayed fault warnings. For example, a capacitor bank in a converter station exploded because the slow decline in capacitance was not detected in time. Utility Model Content

[0016] To address the shortcomings of the existing technology, this utility model provides a distributed capacitive equipment online monitoring device for GIS. This device primarily collects relevant parameters such as current and phase of the capacitive equipment, and collects parameters such as voltage amplitude and phase of the three-phase bus. Both can interact, transmit, synchronize signals, and perform data acquisition and calculation through a single communication bus. This eliminates the traditional method of connecting multiple bus signals to the capacitive equipment, simplifies the wiring of the entire system, avoids interference caused by multiple signal connections, improves the stability of the entire system, and reduces the installation and maintenance costs.

[0017] To achieve the above technical objectives, the present invention adopts the following technical solution: an online monitoring device for distributed capacitive equipment applied to GIS, comprising a bus voltage monitoring device and a capacitive equipment monitoring device;

[0018] The bus voltage monitoring device includes three voltage transformers, which are respectively connected to the three-phase voltages A, B, and C to monitor the voltage amplitude and phase of the three-phase voltages A, B, and C.

[0019] The capacitive device monitoring device includes three zero-flux current transformers, which are respectively connected to three capacitive devices to monitor the total current value and phase of the three capacitive devices.

[0020] The bus voltage monitoring device and the capacitive equipment monitoring device also include a mains voltage transformer, which is connected to the mains power supply to monitor the voltage amplitude and phase of the mains power supply.

[0021] It also includes an RS485 communication module, which is connected to the RS485 communication port of the bus voltage monitoring device and the RS485 communication port of the capacitive equipment monitoring device.

[0022] The three voltage transformer circuits have the same structure. The circuit structure of the mains voltage transformer corresponding to phase A voltage includes voltage transformer CT1 and operational amplifier U14B. Pin 1 of voltage transformer CT1 is connected to resistor R12, and resistor R12 is connected to resistor R11. Pin 3 of voltage transformer CT1 is connected to pin 5 of operational amplifier U14B, and pin 4 of voltage transformer CT1 is grounded. Pin 5 of operational amplifier U14B is connected to resistor R134, and resistor R134 is grounded. Pin 6 of operational amplifier U14B is connected to resistor R16, and resistor R16 is grounded. Pin 7 of operational amplifier U14B is divided into two paths: one path is connected to resistor R15, and resistor R15 is connected to resistor R16; the other path is connected to resistor R133, and resistor R133 is connected to capacitor C66, and capacitor C66 is grounded. Resistor R133 outputs PT_SIGNAL1.

[0023] The three zero-flux current transformers have the same circuit structure. The circuit structure of the one zero-flux current transformer corresponding to phase A current includes operational amplifiers OPB2A, OPB2B, and OPB2C. Pin 1 of operational amplifier OPB2A is divided into two paths: the first path connects to resistor R52, which is connected to pin 2 of OPB2A; the second path connects to resistor R56, which is connected to pin 5 of operational amplifier OPB2B. Pin 2 of operational amplifier OPB2A is also connected to resistor R57, which is connected in parallel to resistor R19 and diode D19. Resistor R19 and diode D19 are connected in parallel and then grounded. Pin 3 of operational amplifier OPB2A is connected to resistor R58. Pin 8 is grounded. Pin 4 of op-amp OPB2A is connected to 15V+ and capacitor C19, with capacitor C19 grounded. Pin 11 of op-amp OPB2A is connected to 15V- and capacitor C21, with capacitor C21 grounded. Pin 5 of op-amp OPB2B is also connected to capacitor C20, with capacitor C20 grounded. Pin 6 of op-amp OPB2B is connected to pin 7 of op-amp OPB2B. Pin 7 of op-amp OPB2B is connected to resistor R55. Resistor R55 is connected to pin 9 of op-amp OPB2C. Pin 9 of op-amp OPB2C is connected to pin 8 of op-amp OPB2C. Pin 10 of op-amp OPB2C is connected to resistor R59, with resistor R59 grounded. Pin 8 of op-amp OPB2C outputs SIGNAL_1.

[0024] The structure of the 1-channel mains voltage transformer is the same as that of the 3-channel voltage transformer.

[0025] In summary, this utility model achieves the following technical effects:

[0026] This invention uses an RS485 communication bus and a high-precision timing module inside the chip to complete the functions of monitoring and synchronizing bus voltage with multiple capacitive devices and synchronizing data sampling, without having to connect the main bus signal to each capacitive device.

[0027] This utility model's capacitive equipment monitoring device mainly collects relevant parameters such as current and phase of capacitive equipment, and collects parameters such as voltage amplitude and phase of the three-phase bus. The two only need to communicate through a single bus to perform data interaction, transmission, signal synchronization, acquisition and calculation functions. It abandons the traditional method of connecting multiple bus signals to capacitive equipment, simplifies the wiring of the entire system, avoids interference problems caused by multiple signal access, improves the stability of the entire system, and reduces the installation and maintenance costs of the entire system. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the bus voltage monitoring device;

[0029] Figure 2 This is a schematic diagram of a 3-channel voltage transformer circuit;

[0030] Figure 3 This is an architecture diagram of a capacitive equipment monitoring device;

[0031] Figure 4 This is a schematic diagram of a 3-channel zero-flux current transformer circuit;

[0032] Figure 5 It is a temperature and humidity transformer circuit;

[0033] Figure 6 This is a system wiring diagram. Detailed Implementation

[0034] The present invention will be further described in detail below with reference to the accompanying drawings.

[0035] This specific embodiment is merely an explanation of the present utility model and is not intended to limit the present utility model. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present utility model, they are protected by patent law.

[0036] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0038] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0039] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0040] Example:

[0041] A distributed capacitive equipment online monitoring device for GIS includes a bus voltage monitoring device and a capacitive equipment monitoring device;

[0042] The bus voltage monitoring device includes three voltage transformers, which are respectively connected to the three-phase voltages A, B, and C to monitor the voltage amplitude and phase of the three-phase voltages A, B, and C.

[0043] The capacitive device monitoring device includes three zero-flux current transformers, which are respectively connected to three capacitive devices to monitor the total current value and phase of the three capacitive devices.

[0044] The bus voltage monitoring device and the capacitive equipment monitoring device also include a mains voltage transformer, which is connected to the mains power supply to monitor the voltage amplitude and phase of the mains power supply.

[0045] It also includes an RS485 communication module, which is connected to the RS485 communication port of the bus voltage monitoring device and the RS485 communication port of the capacitive equipment monitoring device.

[0046] This invention utilizes a bus voltage monitoring device to monitor the three-phase voltages (A, B, and C) and the mains voltage, and a capacitive equipment monitoring device to monitor the current and mains voltage of the three capacitive devices under full current conditions. Both the bus voltage monitoring device and the capacitive equipment monitoring device have a circuit to monitor the mains voltage. This is to use the mains voltage as a reference for phase calculation, ensuring that the phase of the three phases collected by the bus voltage monitoring device and the phase collected by the capacitive equipment monitoring device are simultaneous. The bus voltage monitoring device calculates the phase based on the three-phase voltage and the mains voltage, while the capacitive equipment monitoring device calculates the phase based on the current and the mains voltage of the three capacitive devices under full current conditions. The mains signals from both devices are identical at the same time. As can be seen from the following formula, the phase difference calculation cancels out the variable of the mains signal phase:

[0047]

[0048] Figure 1 This is a diagram of the architecture of the bus voltage monitoring device. Figure 2 This is a schematic diagram of a 3-channel voltage transformer circuit.

[0049] like Figure 1 As shown, the power supply module mainly provides low-voltage power to the entire device, and also has surge protection, common-mode and differential-mode interference signal protection circuits to improve the anti-interference capability of the entire device. Its circuit design is an existing design and will not be described in detail here. The main MCU processing unit is responsible for the core data processing, data calculation, and communication data interaction functions of the entire device. The main MCU processing unit uses an STM32F407ZGT6 chip. The multi-channel 485 communication module is responsible for data interaction with the back-end host, using a standard 485 interface as the physical layer and the standard Modbus-RTU protocol. Three voltage transformer circuits (phase A, phase B, and phase C) and one mains voltage transformer form a sensor signal acquisition circuit, which can acquire the three-phase voltage amplitude and signal, as well as the mains voltage amplitude and phase.

[0050] like Figure 2As shown, the circuit structures of the three voltage transformers are identical. The circuit structure of the mains voltage transformer corresponding to phase A voltage includes voltage transformer CT1 and operational amplifier U14B. Pin 1 of voltage transformer CT1 is connected to resistor R12, and resistor R12 is connected to resistor R11. Pin 3 of voltage transformer CT1 is connected to pin 5 of operational amplifier U14B, and pin 4 of voltage transformer CT1 is grounded. Pin 5 of operational amplifier U14B is connected to resistor R134, and resistor R134 is grounded. Pin 6 of operational amplifier U14B is connected to resistor R16, and resistor R16 is grounded. Pin 7 of operational amplifier U14B is divided into two paths: one path is connected to resistor R15, resistor R15 is connected to resistor R16, and the other path is connected to resistor R133. Resistor R133 is connected to capacitor C66, capacitor C66 is grounded, and resistor R133 outputs PT_SIGNAL1.

[0051] The op-amp U14B is model AD822A.

[0052] Figure 2 This is a schematic diagram of one voltage acquisition channel. The other two channels have the same structure and will not be described in detail here.

[0053] Figure 3 This is an architecture diagram of a capacitive equipment monitoring device. Figure 4 This is a schematic diagram of a 3-channel zero-flux current transformer circuit. Its power supply module is the same as that of the bus voltage monitoring device. The main MCU processing unit uses an STM32F407ZGT6 chip. The multi-channel RS-485 communication module is also the same as that of the bus voltage monitoring device. The 3-channel zero-flux current transformer circuit (corresponding to phases A, B, and C respectively) and 1-channel mains voltage transformer form the acquisition circuit, used to collect the current data and mains voltage of the three phases.

[0054] like Figure 4As shown, the circuit structures of the three zero-flux current transformers are identical. The circuit structure of the one zero-flux current transformer corresponding to phase A current includes operational amplifiers OPB2A, OPB2B, and OPB2C. Pin 1 of operational amplifier OPB2A is divided into two paths: the first path connects to resistor R52, which in turn connects to pin 2 of OPB2A; the second path connects to resistor R56, which in turn connects to pin 5 of operational amplifier OPB2B. Pin 2 of operational amplifier OPB2A is also connected to resistor R57, which in turn connects to a parallel resistor R19 and diode D19. Resistor R19 and diode D19 are connected in parallel and then grounded. Pin 3 of operational amplifier OPB2A is connected to resistor R58. R58 is grounded. Pin 4 of op-amp OPB2A is connected to 15V+ and capacitor C19, which is grounded. Pin 11 of op-amp OPB2A is connected to 15V- and capacitor C21, which is grounded. Pin 5 of op-amp OPB2B is also connected to capacitor C20, which is grounded. Pin 6 of op-amp OPB2B is connected to pin 7. Pin 7 of op-amp OPB2B is connected to resistor R55. Resistor R55 is connected to pin 9 of op-amp OPB2C. Pin 9 of op-amp OPB2C is connected to pin 8. Pin 10 of op-amp OPB2C is connected to resistor R59, which is grounded. Pin 8 of op-amp OPB2C outputs SIGNAL_1.

[0055] The op-amps OPB2A, OPB2B, and OPB2C are modeled as OP4177AR.

[0056] Both devices are also equipped with one mains voltage transformer to monitor the voltage amplitude and phase of the mains power. This mains voltage transformer is connected to... Figure 2 The three voltage transformers shown have the same structure, so they will not be described in detail here.

[0057] like Figure 3 As shown, the capacitive equipment monitoring device is also equipped with one temperature and humidity transformer, combined with... Figure 5 , Figure 5 This is a temperature and humidity transformer circuit. The single-channel temperature and humidity transformer is used to detect ambient temperature and humidity. The single-channel transformer includes a chip U8. Pin 2 is connected to resistor R7 and capacitor C65; resistor R7 is connected to +3.3V, and capacitor C65 is grounded. Pin 3 is connected to resistor R8, which is also connected to +3.3V. Pin 4 is connected to resistor R9, which is also connected to +3.3V. Pin 5 is grounded. This invention can collect and monitor temperature and humidity values ​​in the environment, and correct the test data based on the ambient temperature and humidity values, making the measured values ​​more accurate.

[0058] Figure 6This is a system wiring diagram. The three monitoring devices (capacitive equipment monitoring devices) each correspond to one capacitor and are connected to one phase voltage. This utility model adopts a distributed design method. The capacitive equipment monitoring device mainly collects relevant current and phase parameters of the capacitive equipment, while the bus voltage collects the voltage amplitude and phase parameters of the three-phase bus. The two only need to communicate through a single communication bus to perform data interaction, transmission, signal synchronization, acquisition and calculation functions. This method eliminates the traditional method of connecting multiple bus signals to capacitive equipment, simplifies the wiring of the entire system, avoids interference caused by multiple signal access, improves the stability of the entire system, and reduces the installation and maintenance costs of the entire system.

[0059] The bus voltage monitoring device employs four high-precision voltage transformers (PTs). Three of these transformers monitor the voltage amplitude and phase of phases A, B, and C, while the remaining transformer monitors the voltage amplitude and phase of the mains power. The device then uses a multi-channel RS485 bus to perform time synchronization, sampling, and data synchronization with monitoring devices distributed at the capacitive equipment terminals. The device processes the parameters read from each capacitive equipment and its own measured parameters to calculate the relevant performance parameters of each device. This data is then uploaded to the backend via the RS485 bus for analysis and display.

[0060] The above methods allow for real-time calculation of the performance parameters of various capacitive devices, enabling a more comprehensive assessment of the circuit breaker's lifespan. This helps avoid misjudgments or omissions caused by inaccurate estimations in traditional methods.

[0061] It also features an RS485 communication interface and adopts the standard MODBUS-RTU protocol, which can upload data from various capacitive devices to the smart grid in real time, ensuring the timeliness and accuracy of the data. It can capture even the slightest changes in the operation of capacitive devices at the first moment, providing strong support for subsequent assessment and prediction.

[0062] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model shall fall within the scope of the technical solution of the present utility model.

Claims

1. An online monitoring device for distributed capacitive equipment applied to GIS, characterized in that: This includes bus voltage monitoring devices and capacitive equipment monitoring devices; The bus voltage monitoring device includes three voltage transformers, which are respectively connected to the three-phase voltages A, B, and C to monitor the voltage amplitude and phase of the three-phase voltages A, B, and C. The capacitive device monitoring device includes three zero-flux current transformers, which are respectively connected to three capacitive devices to monitor the total current value and phase of the three capacitive devices. The bus voltage monitoring device and the capacitive equipment monitoring device also include a mains voltage transformer, which is connected to the mains power supply to monitor the voltage amplitude and phase of the mains power supply. It also includes an RS485 communication module, which is connected to the RS485 communication port of the bus voltage monitoring device and the RS485 communication port of the capacitive equipment monitoring device.

2. The distributed capacitive equipment online monitoring device for GIS according to claim 1, characterized in that: The three voltage transformer circuits have the same structure. The circuit structure of the mains voltage transformer corresponding to phase A voltage includes voltage transformer CT1 and operational amplifier U14B. Pin 1 of voltage transformer CT1 is connected to resistor R12, and resistor R12 is connected to resistor R11. Pin 3 of voltage transformer CT1 is connected to pin 5 of operational amplifier U14B, and pin 4 of voltage transformer CT1 is grounded. Pin 5 of operational amplifier U14B is connected to resistor R134, and resistor R134 is grounded. Pin 6 of operational amplifier U14B is connected to resistor R16, and resistor R16 is grounded. Pin 7 of operational amplifier U14B is divided into two paths: one path is connected to resistor R15, and resistor R15 is connected to resistor R16; the other path is connected to resistor R133, and resistor R133 is connected to capacitor C66, and capacitor C66 is grounded. Resistor R133 outputs PT_SIGNAL1.

3. The distributed capacitive equipment online monitoring device for GIS according to claim 1, characterized in that: The three zero-flux current transformers have the same circuit structure. The circuit structure of the one-channel zero-flux current transformer corresponding to phase A current includes operational amplifiers OPB2A, OPB2B, and OPB2C. Pin 1 of operational amplifier OPB2A is divided into two paths: the first path connects to resistor R52, which is connected to pin 2 of OPB2A; the second path connects to resistor R56, which is connected to pin 5 of operational amplifier OPB2B. Pin 2 of operational amplifier OPB2A is also connected to resistor R57, which is connected in parallel to resistor R19 and diode D19. Resistor R19 and diode D19 are connected in parallel and then grounded. Pin 3 of operational amplifier OPB2A is connected to resistor R58. Pin 58 is grounded. Pin 4 of op-amp OPB2A is connected to 15V+ and capacitor C19, which is grounded. Pin 11 of op-amp OPB2A is connected to 15V- and capacitor C21, which is grounded. Pin 5 of op-amp OPB2B is also connected to capacitor C20, which is grounded. Pin 6 of op-amp OPB2B is connected to pin 7. Pin 7 of op-amp OPB2B is connected to resistor R55. Resistor R55 is connected to pin 9 of op-amp OPB2C. Pin 9 of op-amp OPB2C is connected to pin 8. Pin 10 of op-amp OPB2C is connected to resistor R59, which is grounded. Pin 8 of op-amp OPB2C outputs SIGNAL_1.

4. The distributed capacitive equipment online monitoring device for GIS according to claim 1, characterized in that: The structure of the 1-channel mains voltage transformer is the same as that of the 3-channel voltage transformer.

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