GIS equipment partial discharge detection circuit based on SiPM

Abstract

The utility model discloses an SiPM-based GIS equipment partial discharge detection circuit, which relates to the technical field of power equipment fault detection and comprises a power supply module, a bias voltage power supply circuit, an SiPM sensor and a signal processing circuit. Wherein the input end of the bias voltage power supply circuit is electrically connected with the power supply module, the output end of the bias voltage power supply circuit is electrically connected with the power supply end of the SiPM sensor, and the bias voltage power supply circuit is used for providing adjustable voltage for the SiPM sensor; the output end of the SiPM sensor is electrically connected with the input end of the signal processing circuit, and the SiPM sensor is used for detecting an optical signal generated during partial discharge of the GIS equipment and sending a detection signal to the signal processing circuit; the power supply end of the signal processing circuit is electrically connected with the power module. According to the utility model, effective detection of partial discharge of GIS equipment can be realized, and the system has the advantages of high sensitivity and strong anti-interference capability.

Description

Technical Field

[0001] The utility model relates to the technical field of power equipment fault detection, in particular to a SiPM-based GIS equipment partial discharge detection circuit. Background Art

[0002] With the rapid development of the power industry, gas-insulated switchgear (GIS) substations are increasingly being used due to their compact footprint, high reliability, and easy maintenance. GIS devices enclose electrical equipment, including circuit breakers, disconnectors, insulators, grounding switches, busbars, and instrument transformers, within pipes filled with SF6 insulating gas, significantly improving the reliability and safety of power systems. However, as GIS equipment ages, monitoring the insulation material and diagnosing partial discharge faults within it become critical issues for ensuring safe and stable grid operation.

[0003] Partial discharge (PD) is one of the primary precursors to insulation deterioration in GIS equipment. During GIS operation, defects such as air gaps, cracks, metal particles, and insulating gas contamination may develop in the insulation system due to manufacturing defects, improper installation, high arc temperatures during interruption, and insulation aging caused by long-term operation. These defects can easily trigger PD under strong electric fields. Although weak PD does not cause insulation breakdown, prolonged operation can degrade insulation performance and lead to insulation breakdown, resulting in equipment failure and even power grid accidents. Accurate and timely detection of PD in GIS equipment during routine maintenance plays a vital role in preventing insulation failures and ensuring safe power grid operation.

[0004] Traditional partial discharge detection technologies, such as ultrasonic detection, ultra-high frequency (UHF) detection, pulsed current detection, and chemical methods, are capable of detecting partial discharge in GIS equipment to a certain extent. However, these technologies still have limitations in practical application. For example, while UHF detection methods offer high sensitivity, they are susceptible to interference in complex electromagnetic environments. The sensitivity of different types of partial discharge sensors varies significantly, and some noteworthy partial discharge types may have signal spectra that do not reach the UHF band. While ultrasonic detection methods offer strong immunity to electromagnetic interference, they have a limited detection range and make it difficult to locate the discharge location. Pulsed current detection methods have strict requirements for sensor installation location and are susceptible to on-site electromagnetic interference. The attenuation and reflection of current pulse signals can affect detection accuracy and reliability, making sensor deployment and maintenance in complex field environments difficult. Therefore, developing a partial discharge detection technology with high sensitivity, strong anti-interference capabilities, and a wide detection range is crucial for improving the operational safety and reliability of GIS equipment.

[0005] Silicon photomultipliers (SiPMs) are a newly developed photoelectric detection device. Due to their high sensitivity, fast response, low noise, and excellent electromagnetic interference immunity, they offer broad application potential in partial discharge detection. Applying SiPMs to partial discharge detection in power equipment is expected to overcome the limitations of traditional partial discharge detection technology, improve detection sensitivity and reliability, and provide a new solution for condition monitoring and fault diagnosis of GIS equipment. Utility Model Content

[0006] The technical problem to be solved by the utility model is to provide a GIS equipment partial discharge detection circuit based on SiPM, which can realize effective detection of GIS equipment partial discharge and has the advantages of high sensitivity and strong anti-interference ability.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A partial discharge detection circuit for GIS equipment based on SiPM includes a power module, a bias voltage power circuit, a SiPM sensor, and a signal processing circuit. The bias voltage power circuit has an input electrically connected to the power module, and an output electrically connected to a power supply of the SiPM sensor, for providing an adjustable voltage to the SiPM sensor. The output of the SiPM sensor is electrically connected to an input of the signal processing circuit, for detecting an optical signal generated during partial discharge of the GIS equipment and sending a detection signal to the signal processing circuit. The power supply of the signal processing circuit is electrically connected to the power module, and the signal processing circuit is used to convert the detection signal into a voltage signal, amplify, and filter the voltage signal. The output of the signal processing circuit is used to output the amplified and filtered voltage signal.

[0009] The beneficial effects of the utility model are:

[0010] The SiPM-based GIS equipment partial discharge detection circuit provided by the utility model provides a stable and reliable adjustable voltage for the SiPM sensor by designing a bias voltage power supply circuit. The signal processing circuit is designed with low noise, high gain and broadband in mind, which complies with the complex electromagnetic environment of the substation and realizes stable amplification and output of the SiPM sensor output signal. This makes the detection circuit have the advantages of high sensitivity and strong anti-interference ability, meeting the partial discharge detection needs of substation GIS equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a principle block diagram of an embodiment of the utility model.

[0012] Figure 2 It is a circuit connection diagram of the bias voltage power supply circuit of an embodiment of the utility model.

[0013] Figure 3 It is a circuit connection diagram of the signal processing circuit of an embodiment of the utility model.

[0014] Figure 4 This is a partial discharge detection distance effect curve obtained from experiments of the utility model. DETAILED DESCRIPTION

[0015] The present invention is described below in conjunction with the accompanying drawings. The specific implementation methods described here are only used to illustrate and explain the present invention and are not used to limit the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solution of the present invention by ordinary technicians in this field should fall within the scope of protection of the present invention.

[0016] like Figure 1As shown, the SiPM-based partial discharge detection circuit for GIS equipment of this embodiment includes a power module, a bias voltage power circuit, a SiPM sensor and a signal processing circuit.

[0017] The input end of the bias voltage power supply circuit is electrically connected to the power supply module, and the output end thereof is electrically connected to the power supply end of the SiPM sensor, so as to provide an adjustable voltage to the SiPM sensor.

[0018] The output end of the SiPM sensor is electrically connected to the input end of the signal processing circuit, and is used to detect the optical signal generated when the GIS equipment is partially discharged, and send the detection signal to the signal processing circuit.

[0019] The power supply end of the signal processing circuit is electrically connected to the power supply module. The signal processing circuit is used to convert the detection signal into a voltage signal and amplify and filter the voltage signal; the output end of the signal processing circuit is used to output the amplified and filtered voltage signal.

[0020] The SiPM sensor in this embodiment is the MicroFC-60035 SiPM sensor, a new type of high-performance semiconductor photoelectric sensor composed of multiple APD arrays operating in Geiger mode. During partial discharge (PD) within GIS equipment, the SF6 insulating gas undergoes ionization, excitation, and recombination, generating luminescence and characteristic optical radiation. The wavelengths of the optical signals generated by PD in both air and SF6 gas are distributed within the 200-800 nm range, with the most energy-intensive wavelengths concentrated between 300 and 500 nm. The SiPM sensor's spectral response range (approximately 200-900 nm) perfectly covers this wavelength range. Therefore, the SiPM sensor's spectral characteristics are sufficient for detecting GIS PD optical signals.

[0021] like Figure 2 As shown, the bias voltage power supply circuit of this embodiment includes a DC-DC boost converter chip U1, an inductor L1, a diode D1, a resistor R11, a variable resistor R12, and a resistor R13. The SiPM sensor is represented by U2 in the circuit, and the power module is represented by VCC in the circuit.

[0022] In this circuit, the DC-DC boost converter chip U1 adopts the LT1930AES5 power supply chip, and its power input terminal (VIN pin) is connected to its shutdown control terminal ( The ground terminal (GND pin) is electrically connected to the GND terminal.

[0023] Two ends of the inductor L1 are electrically connected to the power input terminal (VIN pin) and the switch node terminal (SW pin) of the DC-DC boost converter chip U1 respectively.

[0024] The anode of the diode D1 is electrically connected to the switch node terminal (SW pin) of the DC-DC boost converter chip U1 , and the cathode is electrically connected to the first connection terminal of the resistor R11 and the power supply terminal of the SiPM sensor respectively.

[0025] The second connection end of the resistor R11 is electrically connected to the first fixed end and the adjustment end of the variable resistor R12, respectively. The second fixed end of the variable resistor R12 is electrically connected to the feedback control end (NFB pin) of the DC-DC boost converter chip U1 and the first connection end of the resistor R13, respectively. The second connection end of the resistor R13 is electrically connected to the GND end and the output end of the SiPM sensor, respectively.

[0026] The typical operating bias voltage of a SiPM sensor is approximately 24V to 30V. Too high or too low a bias voltage will affect its gain, dark count, and photon detection efficiency (PDE). The LT1930AES5 power supply chip is a step-up DC / DC converter that uses a current-mode PWM control architecture. It has a wide output range (up to 34V) and precise feedback regulation capabilities to ensure that the bias voltage of the SiPM sensor is stable at the optimal operating point. It supports conversion from low input voltage (2.6V to 16V) to high output voltage (up to 34V), boosting the low input voltage to the bias voltage required by the SiPM sensor to meet the breakdown voltage (Vbr≈24.7V) and overvoltage requirements ( V=1~5V) requirements.

[0027] Combined circuit Figure 2 The LT1930AES5 power chip's boost process controls the charge and discharge cycles of inductor L1 (10μH) through an internal switching tube, raising the voltage provided by the power module to the target output voltage. The output voltage is sampled by a voltage divider resistor (resistor R11, variable resistor R12, and resistor R13) and fed back to the chip's internal error amplifier via the NFB pin, dynamically adjusting the switching duty cycle to stabilize the output voltage. Diode D1 (model MBR0540) in the circuit is a freewheeling diode used to ensure a continuous flow path for the inductor current. According to the LT1930AES5 power chip's data sheet, its feedback voltage (Vfb) is 1.25V. Therefore, the formula for calculating the voltage Vbis at the SiPM sensor's power supply terminal is:

[0028] By adjusting the variable resistor R12, Vbias can be made to work at the bias voltage required by the SiPM sensor.

[0029] In addition, the bias voltage power supply circuit also includes capacitors C11, C12, C13, C14, C15, C21, and resistor R21. Capacitor C11 has a first connection end electrically connected to the power input terminal (VIN pin) of the power module and the DC-DC boost converter chip U1, respectively, and a second connection end electrically connected to the GND terminal. Capacitor C12 has a first connection end electrically connected to the first connection end of capacitor C11, and a second connection end electrically connected to the second connection end of capacitor C11. Capacitor C13 has a first connection end electrically connected to the first connection end of resistor R11, and a second connection end electrically connected to the second fixed end of variable resistor R12. Capacitor C14 has a first connection end electrically connected to the first connection end of capacitor C13, and a second connection end electrically connected to the GND terminal. Capacitor C15 has a first connection end electrically connected to the first connection end of capacitor C14, and the other end electrically connected to the GND terminal. The first connection end of capacitor C21 is electrically connected to the first connection end of capacitor C15 and the power supply end of the SiPM sensor respectively, the second connection end is electrically connected to the GND end and the first connection end of resistor R21 respectively, and the second connection end of resistor R21 is electrically connected to the output end of the SiPM sensor.

[0030] The LT1930AES5 power supply chip, combined with ceramic capacitors (capacitors C11, C12, C13, C14, C15, and C21) for filtering, delivers output ripple as low as 10mVpp (mVpp). This millivolt-level output noise reduces interference with weak partial discharge signals, preventing noise from interfering with the SiPM sensor's weak signal detection and improving detection sensitivity. Furthermore, the LT1930AES5 power supply chip's high switching frequency enables fast transient response, ensuring the SiPM sensor's bias voltage remains stable during load changes (such as partial discharge pulses), preventing signal distortion.

[0031] Therefore, the bias voltage power supply circuit realizes a low-noise, high-stability bias power supply based on the LT1930AES5 power supply chip, meeting the high-voltage bias requirement of partial discharge detection of SiPM sensors.

[0032] like Figure 3 As shown, the signal processing circuit of this embodiment includes a first operational amplifier U3, a second operational amplifier U4, a capacitor C32, a resistor R31, a resistor R42, and a resistor R43. The first operational amplifier U3 and the second operational amplifier U4 are both OPA657N operational amplifiers, and the power supply module is represented by VCC in the circuit.

[0033] In the circuit, the power supply terminal of the first operational amplifier U3 is electrically connected to the power module, the non-phase input terminal is electrically connected to the GND terminal, and the inverting input terminal is electrically connected to the output terminal of the SiPM sensor.

[0034] The power supply terminal of the second operational amplifier U4 is electrically connected to the power module, the non-inverting input terminal is electrically connected to the GND terminal, and the output terminal is used to output a signal.

[0035] A first connection end of the capacitor C32 is electrically connected to the inverting input end of the first operational amplifier U3 and the output end of the SiPM sensor, respectively, and a second connection end is electrically connected to the output end of the first operational amplifier U3.

[0036] The first connection end of the resistor R31 is electrically connected to the first connection end of the capacitor C32 and the output end of the SiPM sensor respectively, and the second connection end is electrically connected to the second connection end of the capacitor C32 and the first connection end of the resistor R42 respectively.

[0037] The second connection end of the resistor R42 is electrically connected to the inverting input end of the second operational amplifier U4 and the first connection end of the resistor R43 respectively.

[0038] The second connection end of the resistor R43 is electrically connected to the output end of the second operational amplifier U4.

[0039] The OPA657N operational amplifier effectively amplifies the weak current pulses output by SiPM sensors, significantly improving the sensitivity of partial discharge signal detection and preventing signal distortion. It also features fast response and a high slew rate, ensuring complete capture of partial discharge pulses and meeting the requirements for transient discharge detection in substation GIS equipment. It also supports transimpedance amplifier (TIA) configuration, using feedback capacitors to compensate for parasitic capacitance, suppressing high-frequency oscillations and improving system stability. Its wideband signal processing capability reaches 275MHz, covering the high-frequency components of partial discharge signals and effectively preventing distortion in the amplified signal output. Integrated ESD protection and an optimized structural design ensure stable operation in complex electromagnetic environments. It offers strong flexibility and scalability, supporting single-supply voltage division, facilitating the construction and installation of real-time partial discharge monitoring modules for substation GIS equipment.

[0040] Based on the above circuit structure, the signal processing circuit further includes a capacitor C31, a capacitor C41, and a resistor R41. The two ends of capacitor C31 are electrically connected to the non-inverting input and inverting input of the first operational amplifier U3, respectively. The two ends of capacitor C41 are electrically connected to the inverting input and output of the second operational amplifier U4, respectively. Resistor R41 is connected in series between the non-inverting input and GND of the second operational amplifier U4.

[0041] Combined circuit Figure 3The core function of this signal processing circuit is to convert the weak current pulse signal (detection signal) output by the SiPM sensor into a voltage signal with a high signal-to-noise ratio, and amplify and filter it through two stages of OPA657N operational amplifiers. The amplified and filtered voltage signal is output from the output end of the second operational amplifier U4.

[0042] Of the two operational amplifiers, the first operational amplifier U3 forms a transimpedance amplifier (TIA) that converts the SiPM sensor's current pulses into voltage signals. The parallel capacitor C32 is used to compensate for high-frequency phase margin and prevent oscillation. The transimpedance gain is calculated as follows:

[0043] Vout = Iin × R31

[0044] The actual bandwidth frequency is determined by the feedback resistance and capacitance, and is calculated as follows:

[0045] The second operational amplifier U4 forms an inverting amplifier and a low-pass filter, amplifying the voltage signal output by the first operational amplifier U3 and using the feedback network to form a filter to suppress high-frequency noise. The voltage gain calculation formula is as follows:

[0046] This signal processing circuit takes anti-interference performance into account. The first operational amplifier, U3, suppresses high-frequency oscillations, while the second operational amplifier, U4, provides low-pass filtering to effectively remove electromagnetic noise (such as switching noise) in the substation environment. A two-stage gain distribution balances sensitivity and output amplitude to avoid premature saturation. This circuit combines the high gain of the SiPM sensor with the low noise characteristics of the OPA657N operational amplifier to achieve non-invasive, highly sensitive partial discharge detection.

[0047] In order to test the performance of the local discharge detection circuit of the SiPM sensor in terms of detection distance, this embodiment designed a set of experiments for testing, and used a multimeter to measure the voltage of the output voltage Vout under different detection distances. In order to improve the gain and sensitivity level of the SiPM sensor, the bias voltage is adjusted to 29V. A YSKJ-18 high-voltage generator is used to simulate continuous weak local discharge. The illumination measured by a DELIXI1802 illuminance meter at a distance of 0.05m from the discharge end is only 0.5lx, and the light generated by the discharge is very weak. In the absence of local discharge, the output voltage Vout is measured by a multimeter to be 0.35V. The experimental test data are shown in Table 1. A relatively obvious and stable local discharge signal can be normally detected within a range of 8 meters; when the distance is less than or equal to 1.1m, the output voltage Vout is 4.85V, which has reached saturation. As shown in Table 1 Figure 4The following graph shows the partial discharge detection distance data. With a bias voltage of 29V, the effective partial discharge detection distance reaches 8 meters. The closer the detection distance, the greater the output voltage.

[0048] Table 1

[0049]

[0050] In summary, the partial discharge detection circuit of GIS equipment based on SiPM in this embodiment designs a bias voltage power supply circuit based on the LT1930AES5 power supply chip to provide a stable and reliable adjustable voltage for the SiPM sensor, and designs a two-stage amplification circuit based on the OPA657N operational amplifier, which takes into account the low noise, high gain and broadband signal processing requirements, conforms to the complex electromagnetic environment of the substation, and realizes the stable amplification output of the SiPM sensor output signal, so that the detection circuit has the advantages of high sensitivity and strong anti-interference ability, meeting the partial discharge detection requirements of substation GIS equipment.

Claims

1. A partial discharge detection circuit for GIS equipment based on SiPM, characterized by: It includes a power module, a bias voltage power circuit, a SiPM sensor and a signal processing circuit; wherein, The input end of the bias voltage power supply circuit is electrically connected to the power supply module, and the output end is electrically connected to the power supply end of the SiPM sensor, which is used to provide an adjustable voltage to the SiPM sensor; the bias voltage power supply circuit includes a DC-DC boost converter chip, an inductor L1, a diode D1, a resistor R11, a variable resistor R12 and a resistor R13; the power input end of the DC-DC boost converter chip is electrically connected to its shutdown control end and the power supply module respectively, and its ground end is electrically connected to the GND end; the two ends of the inductor L1 are respectively connected to the power input end and the power supply end of the DC-DC boost converter chip. The switch node end is electrically connected; the positive electrode of the diode D1 is electrically connected to the switch node end of the DC-DC boost converter chip, and the negative electrode is electrically connected to the first connection end of the resistor R11 and the power supply end of the SiPM sensor respectively; the second connection end of the resistor R11 is electrically connected to the first fixed end and the adjustment end of the variable resistor R12 respectively, the second fixed end of the variable resistor R12 is electrically connected to the feedback control end of the DC-DC boost converter chip and the first connection end of the resistor R13 respectively, and the second connection end of the resistor R13 is electrically connected to the GND end and the output end of the SiPM sensor respectively; The output end of the SiPM sensor is electrically connected to the input end of the signal processing circuit, and is used to detect the optical signal generated by the partial discharge of the GIS equipment and send the detection signal to the signal processing circuit; The power supply end of the signal processing circuit is electrically connected to the power supply module. The signal processing circuit is used to convert the detection signal into a voltage signal and amplify and filter the voltage signal; the output end of the signal processing circuit is used to output the amplified and filtered voltage signal.

2. The SiPM-based GIS equipment partial discharge detection circuit according to claim 1, characterized in that: The bias voltage power supply circuit further includes a capacitor C11, a capacitor C12, a capacitor C13, a capacitor C14, a capacitor C15, a capacitor C21 and a resistor R21; wherein the first connection end of the capacitor C11 is electrically connected to the power input end of the power module and the DC-DC boost converter chip respectively, and the second connection end is electrically connected to the GND end; the first connection end of the capacitor C12 is electrically connected to the first connection end of the capacitor C11, and the second connection end is electrically connected to the second connection end of the capacitor C11; the first connection end of the capacitor C13 is electrically connected to the first connection end of the resistor R11, and the second connection end is electrically connected to the GND end. The second fixed end of the variable resistor R12 is electrically connected; the first connection end of the capacitor C14 is electrically connected to the first connection end of the capacitor C13, and the second connection end is electrically connected to the GND end; the first electrical connection end of the capacitor C15 is electrically connected to the first connection end of the capacitor C14, and the other end is electrically connected to the GND end; the first connection end of the capacitor C21 is electrically connected to the first connection end of the capacitor C15 and the power supply end of the SiPM sensor, respectively, and the second connection end is electrically connected to the GND end and the first connection end of the resistor R21, respectively, and the second connection end of the resistor R21 is electrically connected to the output end of the SiPM sensor.

3. The SiPM-based GIS equipment partial discharge detection circuit according to claim 1, characterized in that: The DC-DC boost converter chip is an LT1930AES5 chip.

4. The SiPM-based GIS equipment partial discharge detection circuit according to claim 1, characterized in that: The signal processing circuit includes a first operational amplifier, a second operational amplifier, a capacitor C32, a resistor R31, a resistor R42 and a resistor R43; wherein, the power supply end of the first operational amplifier is electrically connected to the power supply module, the non-phase input end is electrically connected to the GND end, and the inverting input end is electrically connected to the output end of the SiPM sensor; the power supply end of the second operational amplifier is electrically connected to the power supply module, the non-phase input end is electrically connected to the GND end, and the output end is used to output a signal; the first connection end of the capacitor C32 is electrically connected to the inverting input end of the first operational amplifier and the output end of the SiPM sensor, respectively, and the second connection end is electrically connected to the output end of the first operational amplifier; the first connection end of the resistor R31 is electrically connected to the first connection end of the capacitor C32 and the output end of the SiPM sensor, respectively, and the second connection end is electrically connected to the second connection end of the capacitor C32 and the first connection end of the resistor R42; the second connection end of the resistor R42 is electrically connected to the inverting input end of the second operational amplifier and the first connection end of the resistor R43, respectively; the second connection end of the resistor R43 is electrically connected to the output end of the second operational amplifier.

5. The SiPM-based GIS equipment partial discharge detection circuit according to claim 4, characterized in that: The signal processing circuit also includes a capacitor C31, a capacitor C41 and a resistor R41; wherein the two ends of the capacitor C31 are electrically connected to the non-inverting input terminal and the inverting input terminal of the first operational amplifier respectively; the two ends of the capacitor C41 are electrically connected to the inverting input terminal and the output terminal of the second operational amplifier respectively; and the resistor R41 is connected in series between the non-inverting input terminal and the GND terminal of the second operational amplifier.

6. The SiPM-based GIS equipment partial discharge detection circuit according to claim 4, characterized in that: The first operational amplifier and the second operational amplifier are both OPA657N operational amplifiers.

7. The SiPM-based GIS equipment partial discharge detection circuit according to claim 1, characterized in that: The SiPM sensor is a MicroFC-60035 SiPM sensor.

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