Adapter for monitoring partial discharge and dielectric loss of high-voltage bushing

Abstract

The utility model discloses an adapter for monitoring partial discharge and dielectric loss of a high-voltage bushing, which comprises a power supply system, a tail end sensor, an electrode monitoring module, an electromagnetic wave monitoring module, a signal conditioning module, an AD high-speed signal acquisition module and a central processing unit, the electrode monitoring module is electrically connected to the tail end sensor, the electromagnetic wave monitoring module is electrically connected to the tail end sensor, the electromagnetic wave monitoring module is electrically connected to the power supply system, and the signal conditioning module is electrically connected to the electrode monitoring module and the electromagnetic wave monitoring module. The AD high-speed signal acquisition module is electrically connected to the signal conditioning module and the power supply system, and the central processing unit is electrically connected to the AD high-speed signal acquisition module and the power supply system. The utility model relates to the field of power equipment monitoring, in particular to an adapter for monitoring partial discharge and dielectric loss of a high-voltage bushing.

Description

Technical Field

[0001] This utility model relates to the field of power equipment monitoring, specifically to an adapter for monitoring partial discharge and dielectric loss in high-voltage bushings. Background Technology

[0002] With the rapid development of my country's economy, on the one hand, the demand for the stability of power supply is increasing, and the requirements for the reliability of power supply equipment are becoming more and more stringent; on the other hand, the losses caused by power outages per unit of time are also increasing.

[0003] For power systems and power user substations, the stable operation of transformers is one of the key aspects. High-voltage bushings are critical equipment in power systems, used for the conduction of current in large electrical equipment such as transformers and switchgear. During long-term operation, high-voltage bushings may experience partial discharge and dielectric loss due to environmental factors, insulation aging, and other reasons. These phenomena are important early warning signs of power equipment failures.

[0004] In existing technologies, the monitoring of partial discharge and dielectric loss is mostly carried out separately, usually requiring two different adapters to monitor partial discharge and dielectric loss respectively. This not only increases equipment costs but also causes inconvenience to on-site operation and maintenance. Utility Model Content

[0005] This invention aims to develop an adapter capable of simultaneously monitoring partial discharge and dielectric loss, which is of great significance for improving monitoring efficiency and reducing operation and maintenance costs.

[0006] To solve the above problems, the technical solution adopted by this utility model is as follows: This utility model is an adapter for monitoring partial discharge and dielectric loss of high-voltage bushings, including a power supply system, and further including an end sensor, an electrode monitoring module, an electromagnetic wave monitoring module, a signal conditioning module, an AD high-speed signal acquisition module, and a central processing unit. The end sensor is electrically connected to the power supply system, the electrode monitoring module is electrically connected to the end sensor, the electromagnetic wave monitoring module is electrically connected to the end sensor, the electromagnetic wave monitoring module is electrically connected to the power supply system, the signal conditioning module is electrically connected to the electrode monitoring module and the electromagnetic wave monitoring module, the AD high-speed signal acquisition module is electrically connected to the signal conditioning module and the power supply system, and the central processing unit is electrically connected to the AD high-speed signal acquisition module and the power supply system.

[0007] Furthermore, the electrode monitoring module is used to collect leakage current signals from the high-voltage bushing.

[0008] Furthermore, the electromagnetic wave monitoring module is used to collect the partial discharge signal of the high-voltage bushing.

[0009] Furthermore, the electromagnetic wave monitoring module employs a high-precision, high-frequency current transformer to capture electromagnetic wave signals in the bushing, and uses high-frequency current signals to characterize the strength of partial discharge.

[0010] Furthermore, the signal conditioning module is used to filter noise and electromagnetic interference, and enhance the signal for easier backend acquisition and processing.

[0011] Furthermore, the AD high-speed signal acquisition module converts the front-end acquired signal into a digital signal suitable for the processor.

[0012] Furthermore, the AD high-speed signal acquisition module is a 12-bit acquisition circuit.

[0013] Furthermore, the central processing unit converts the front-end acquired signals into digital signals suitable for the processor.

[0014] Preferably, it also includes a leakage current acquisition module comprising a high-precision current transformer, a filter circuit, and an amplifier circuit, used to remove interference from the signal and enhance the effective signal, and finally perform AD conversion and processing.

[0015] The beneficial effects of this utility model by adopting the above structure are as follows:

[0016] 1. Integrated design: This adapter integrates partial discharge and dielectric loss sensors into one unit, enabling simultaneous online monitoring of two important parameters, which greatly reduces the cost and maintenance difficulty of monitoring equipment.

[0017] 2. High-precision monitoring: Through high-precision sensors and advanced signal processing methods, it can accurately capture partial discharge signals and leakage current signals, greatly improving monitoring accuracy.

[0018] 3. High reliability: Under the premise of ensuring electrical contact and sealing performance, it can reliably extract the grounding current signal of the bushing end screen without affecting the safe operation of the bushing.

[0019] 4. Easy to install and use, the adapter has a simplified design and small size, making it highly adaptable. It can quickly complete the installation and commissioning of the adapter during the short downtime of the transformer.

[0020] This invention provides a real-time, long-term online monitoring system for partial discharge and dielectric loss in the high-voltage bushings of transformers in substations, accurately reflecting the transformer's operating status. This not only accumulates important empirical data for condition-based maintenance but also provides a theoretical basis for condition-based maintenance. Attached Figure Description

[0021] Figure 1 This is a circuit module diagram of the present invention;

[0022] Figure 2This is the circuit diagram of the end sensor of this utility model;

[0023] Figure 3 This is a diagram of the AD high-speed signal acquisition module of this utility model. Detailed Implementation

[0024] As per the instruction manual Figures 1-3 As shown, this utility model is an adapter for monitoring partial discharge and dielectric loss of high-voltage bushings. It includes a power supply system, as well as an end sensor, an electrode monitoring module, an electromagnetic wave monitoring module, a signal conditioning module, an AD high-speed signal acquisition module, and a central processing unit. The end sensor is electrically connected to the power supply system and is powered by the power supply system.

[0025] The electrode monitoring module is electrically connected to the end sensor. This module is used to collect the leakage current signal of the high-voltage bushing. Bushing dielectric loss (dielectric loss) refers to the energy loss of the high-voltage bushing under a high-voltage electric field, reflecting the insulation condition of the bushing. Dielectric loss is typically measured by calculating the dielectric loss factor (tanδ), which represents the ratio of the conductive current to the capacitive current of the dielectric. A higher dielectric loss factor indicates poorer insulation performance. Therefore, the measuring electrode unit uses a high-precision current transformer to collect the bushing leakage current and converts it into a corresponding voltage signal. The input is 0~700mA, and the corresponding output voltage signal is 0~3.53V for processing by the signal processing unit.

[0026] The electromagnetic wave monitoring module is electrically connected to both the end sensor and the power supply system. It is used to acquire partial discharge signals from the high-voltage bushing. The module employs a high-precision, high-frequency current transformer to capture electromagnetic wave signals within the bushing and uses high-frequency current signals to characterize the strength of the partial discharge.

[0027] Partial discharge (PD) in bushings refers to partial discharge within the high-voltage bushings of power equipment. This discharge is a manifestation of localized damage to the insulation layer of the high-voltage equipment. Prolonged presence of PD accelerates insulation aging and ultimately leads to insulation failure. Partial discharge generates high-frequency electromagnetic waves. Therefore, the electromagnetic wave monitoring module employs a high-precision, high-frequency current transformer to capture electromagnetic wave signals within the bushing and uses high-frequency current signals to characterize the strength of the PD.

[0028] The signal conditioning module is electrically connected to the electrode monitoring module and the electromagnetic wave monitoring module. It filters noise and electromagnetic interference, and enhances the signal for easier downstream acquisition and processing. The signal conditioning module mainly consists of two parts: signal filtering and amplification. Since the signal acquired by the signal acquisition unit contains a large amount of noise, especially electromagnetic interference, a bandpass filter is used to remove the noise, allowing the specific frequency band signal we need to pass through for downstream amplification and processing. The bushing dielectric loss and partial discharge signals acquired by the acquisition unit are very weak, so an amplification circuit is needed to enhance the signal and make it suitable for subsequent processing. The operational amplifier selected here is the LM158DT, a dual-channel low-power differential operational amplifier. It features single or dual power supply operation, high open-loop gain, internal compensation, high common-mode range, good temperature stability, and output short-circuit protection.

[0029] The high-speed AD signal acquisition module is electrically connected to the signal conditioning module and the power supply system, while the central processing unit (CPU) is also electrically connected to both. The AD signal acquisition module primarily targets AC signals with an effective value of 0~3.53V output from sensors. Acquiring AC signals places high demands on the sampling rate of the ADC chip; therefore, the AD9228 ADC was selected as the main chip, forming a 4-channel, 12-bit acquisition circuit. It uses a single 1.8V power supply and a differential clock signal, and incorporates on-chip sample-and-hold circuitry. For most applications, it requires no external reference voltage source or driver device and is compatible with various interfaces.

[0030] The central processing unit (CPU) converts the front-end acquired signals into digital signals suitable for the processor. The CPU's main controller is an STMicroelectronics STM32F103RCT6, a 32-bit ARM Cortex-M3 processor with a maximum clock speed of 72MHz, featuring high performance and low power consumption. It has 256KB of Flash memory and 20KB of SRAM memory, supporting SWD and JTAG. Peripheral resources include: three 12-bit ADCs and two 12-bit DAs; two DMAs supporting TIMER, ADC, DAC, SDIO, I2S, SPI, I2C, and UART; 11 timers (16-bit, two advanced, four general-purpose, two basic timers, two watchdogs, one tick timer systick, 24-bit); two I2C interfaces; five serial ports (USART1, USART2, USART3, UART4, USART5); three SPI interfaces, two IIS interfaces, one CAN interface, one USB interface, and one SDIO.

[0031] It also includes a leakage current acquisition module, which consists of a high-precision current transformer, a filter circuit, and an amplifier circuit, used to remove interference from the signal and enhance the effective signal, and finally perform AD conversion and processing.

[0032] Dielectric loss monitoring measures the leakage current of the high-voltage bushing using a high-precision current transformer. After bandpass filtering and amplification, the signal is sent to the signal processing unit to calculate the dielectric loss factor (tanδ) in conjunction with the high-voltage bus voltage. Simultaneously, the dielectric loss is calculated using an algorithm based on the phase difference between the acquired current and the reference voltage.

[0033] The partial discharge signal around the bushing is captured by a high-precision, high-frequency current transformer. The captured signal is then processed by bandpass filtering and amplification, and sent to the signal processing unit for processing and calculation via a shielded cable.

[0034] It should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A high voltage bushing partial discharge and dielectric loss monitoring adapter comprising a power supply system, characterized by: The terminal sensor is electrically connected to the power supply system, the electrode monitoring module is electrically connected to the terminal sensor, the electromagnetic wave monitoring module is electrically connected to the terminal sensor, the electromagnetic wave monitoring module is electrically connected to the power supply system, the signal conditioning module is electrically connected to the electrode monitoring module and the electromagnetic wave monitoring module, the AD high-speed signal acquisition module is electrically connected to the signal conditioning module and the power supply system, and the central processing unit is electrically connected to the AD high-speed signal acquisition module and the power supply system.

2. The adapter for monitoring partial discharge and dielectric loss of a high voltage bushing according to claim 1, characterized in that: The electrode monitoring module is used for collecting the high-voltage bushing leakage current signal.

3. The adapter for monitoring partial discharge and dielectric loss of a high voltage bushing according to claim 1, characterized in that: The electromagnetic wave monitoring module is used for collecting the partial discharge signal of the high-voltage bushing.

4. The adapter for monitoring partial discharge and dielectric loss of a high voltage bushing according to claim 3, characterized in that: The electromagnetic wave monitoring module adopts a high-precision high-frequency current transformer to capture the electromagnetic wave signal in the bushing, and the strength of the partial discharge is represented by the high-frequency current signal.

5. The adapter for monitoring partial discharge and dielectric loss of a high voltage bushing according to claim 1, characterized in that: The signal conditioning module is used for filtering noise and electromagnetic interference, and enhancing the signal for the convenience of the back-end acquisition and processing.

6. The adapter for monitoring partial discharge and dielectric loss of a high voltage bushing according to claim 1, characterized in that: The AD high-speed signal acquisition module converts the front-stage acquisition signal into a digital signal suitable for the processor.

7. The adapter for monitoring partial discharge and dielectric loss of a high voltage bushing according to claim 6, characterized in that: The AD high-speed signal acquisition module is a 12-bit acquisition circuit.

8. The adapter for monitoring partial discharge and dielectric loss of a high voltage bushing according to claim 1, characterized in that: The central processing unit converts the front-stage acquisition signal into a digital signal suitable for the processor.

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