Distribution transformer operation gear operation and maintenance device

Abstract

The utility model discloses a distribution transformer operation gear operation and maintenance device, which belongs to the field of intelligent operation and maintenance devices and comprises a distribution network intelligent analyzer connected with a power grid server through wireless encryption remote transmission equipment. The distribution network intelligent analyzer is connected with a voltage sampling module and a current sensor which are used for acquiring measurement data through a wireless transmission module, the voltage sampling module comprises a high-voltage sampling module and a low-voltage sampling module, and a protection circuit and a temperature detection circuit are arranged in the high-voltage sampling module; the low-voltage sampling module is composed of a TMD3003 type alternating-current voltage measuring module and an overcurrent protection circuit, the current sensor comprises a high-voltage current sensor and a low-voltage secondary current clamp, and the high-voltage sampling module and the high-voltage current sensor are connected with the distribution transformer tail end through a high-voltage measuring rod. The low-voltage sampling module and the low-voltage secondary current clamp are connected with the low-voltage side of the distribution transformer through the low-voltage measuring clamp. The device is accurate in measurement, rich in function and high in practicability.

Description

Technical Field

[0001] The utility model relates to an online testing and intelligent operation and maintenance processing device, in particular to an operation and maintenance device for an operating gear of a distribution transformer. Background Art

[0002] In the 10kV distribution network, the operating gear of the distribution transformer is crucial to the comprehensive management of the distribution network and to ensure the voltage stability on the user side. On the one hand, a single distribution transformer gear calibration cannot provide sufficient reference for the operation stability and comprehensive operation and maintenance management of the distribution station. Therefore, a lot of on-site work and technical personnel support are required. Carrying a variety of test equipment to detect the voltage, current and other data at the end of the distribution transformer is cumbersome and the workload is huge, and it is impossible to provide intelligent operation and maintenance management strategies. On the other hand, the commonly used high-voltage voltage measurement resistor divider method is easily affected by the temperature drift of the resistor, and the test accuracy is low. In addition, the sampling data will be affected by various circuit environments on site during the transmission process, and the data stability and accuracy are low, which affects the accuracy of the gear calculation. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a distribution transformer operating gear operation and maintenance device, to improve and protect the voltage sampling circuit, to improve the accuracy of live calibration measurement of the distribution transformer gear, and at the same time to achieve accurate online calibration of the distribution transformer gear and intelligent operation and maintenance of the distribution transformer with the help of PC.

[0004] In order to solve the above technical problems, the technical solution adopted by the utility model is: a distribution transformer operation gear operation and maintenance device, including a distribution network intelligent analyzer, the distribution network intelligent analyzer is connected to the power grid service end through a wireless encryption remote transmission device, and the distribution network intelligent analyzer is connected to a voltage sampling module and a current sensor for obtaining measurement data through a wireless transmission module. The voltage sampling module includes a high-voltage sampling module and a low-voltage sampling module, wherein the high-voltage sampling module can convert a 10kV high voltage into a 0-3.3V voltage signal through the principle of resistance voltage division, and an AD digital conversion sampling circuit is provided in the high-voltage sampling module, and the sampling circuit is provided There is a low-voltage voltage-dividing resistor R5, and voltage-dividing resistors R1, R2, R3 and R4 are arranged between R5 and the high-voltage line at the distribution transformer end, and control switches S1, S2, S3 and S4 are arranged correspondingly on each voltage-dividing resistor; a temperature detection circuit is also arranged near R5; the low-voltage sampling module is composed of a TMD3003 AC voltage measurement module and a matching overcurrent protection circuit, and the current sensor includes a high-voltage current sensor and a low-voltage secondary current clamp, the high-voltage voltage sampling module and the high-voltage current sensor are connected to the distribution transformer end through a high-voltage measuring rod, and the low-voltage voltage sampling module and the low-voltage secondary current clamp are connected to the distribution transformer end through a low-voltage measuring clamp.

[0005] A further improvement of the technical solution of the utility model is that the temperature detection circuit includes a thermistor PT100, a resistor R7 is arranged in parallel on PT100, a voltage divider resistor R6 is connected to R7, an embedded chip MCU is connected to R7, and the MCU is communicatively connected to the distribution network intelligent analyzer.

[0006] A further improvement of the technical solution of the utility model is that the wireless transmission module is a Lora communication module, and the communication chip is a Semtech SX127x.

[0007] A further improvement of the technical solution of the utility model is that the distribution network intelligent analyzer is a PC that performs operation gear calculation, impedance calculation and three-phase unbalance test of the distribution transformer.

[0008] A further improvement of the technical solution of the utility model is that multiple layers of insurance insulation layers are arranged outside the high-voltage measuring rod and the low-voltage measuring clamp.

[0009] A further improvement of the technical solution of the utility model is that the voltage sampling module and the current sensor have built-in rechargeable batteries and do not need to be powered on site.

[0010] Due to the adoption of the above technical scheme, the technical progress achieved by the utility model is: the voltage sampling module and the current sensor are connected to the distribution network intelligent analyzer by a wireless transmission module to achieve isolation protection for information transmission, and effectively improve the stability and anti-interference ability of data transmission. The circuit in the high-voltage sampling module is improved, and by setting a voltage-dividing resistor and two sets of switches that can be freely switched for testing, the measurement error caused by the temperature drift of the high-voltage voltage-dividing resistor can be effectively avoided during repeated voltage tests. By setting a temperature detection circuit near the low-voltage voltage-dividing resistor, the communication connection between the MCU and the distribution network intelligent analyzer can timely transmit the resistor overheating fault alarm information to the intelligent analyzer, monitor the temperature change, and realize the temperature over-limit alarm. By connecting the distribution network intelligent analyzer as a PC, the computing power of the PC is used to realize the calculation of the current operating gear of the distribution transformer, and the distribution transformer impedance and three-phase imbalance can be calculated according to the voltage and current signal sampling data of the high and low voltage measurement of the distribution transformer, so as to realize the power quality analysis, and then give the distribution transformer gear adjustment plan and operation and maintenance opinions, ensure the voltage quality, and improve the stability of power grid operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

[0012] Figure 1It is a schematic diagram of the structure of the utility model;

[0013] Figure 2 This is a schematic diagram of the circuit of the high voltage sampling module of the utility model;

[0014] Figure 3 This is a schematic diagram of a temperature detection circuit of the utility model. DETAILED DESCRIPTION

[0015] The present invention is further described in detail below in conjunction with the embodiments:

[0016] like Figure 1 As shown, it is a structural diagram of a distribution transformer operating gear operation and maintenance device, including a distribution network intelligent analyzer with computing power, which needs to use computing power to issue adjustment plans and operation and maintenance opinions. In this embodiment, the specific distribution network intelligent analyzer is a PC, and the distribution network intelligent analyzer is connected to the power grid service end through a wireless encryption remote transmission device. The distribution network intelligent analyzer is connected to a voltage sampling module and a current sensor for obtaining measurement data through a wireless transmission module. The wireless transmission module is a Lora communication module, and the communication chip is Semtech SX127x. The use of a wireless communication module to transmit data is more stable and has strong anti-interference, and is not affected by the multi-circuit environment on site. The voltage sampling module includes a high-voltage sampling module and a low-voltage sampling module, and the sampling principle of the high-voltage sampling module is as follows Figure 2 As shown, line A and line B are high-voltage lines at the end of the distribution transformer. The high-voltage sampling module needs to convert the 10kV high voltage into a 0-3.3V voltage signal through the resistor voltage division principle. At the same time, in order to eliminate the influence of resistor temperature drift, two sets of switches are configured, that is, the AD digital conversion circuit collects the voltage across the low-voltage voltage-dividing resistor R5. Voltage-dividing resistors R1, R2, R3 and R4 are set between the voltage-dividing resistor R5 and the high-voltage line A line and line B. Control switches S1, S2, S3 and S4 are set on each voltage-dividing resistor, where S1 and S3 are a group, and S2 and S4 are a group. During the measurement process, one set of switches must be closed and one set of switches must be disconnected. For example, when S1 and S3 are closed and S2 and S4 are disconnected, only R1, R5 and R3 are connected in series in the loop between AB. The A and B lines at the end of the distribution transformer and the high-voltage sampling module are connected through a high-voltage measuring rod. During high-voltage measurement, during repeated multiple voltage tests, the two sets of switches can automatically switch the test, which can effectively avoid the influence of measurement errors caused by resistor temperature drift. At the same time, in order to better monitor the temperature, a temperature detection circuit is set near R5. The temperature detection circuit is as follows Figure 3As shown, it includes a thermistor PT100, a voltage divider resistor R7 is arranged in parallel on the thermistor PT100, R6 and a filter circuit are connected to R7, and the filter circuit includes R8, C2, and a voltage clamp protection diode D1. After the thermistor R5 is connected in parallel with the resistor R7, the resistance value and the voltage value corresponding to the voltage divider of R6 are transmitted to the embedded chip MCU. The MCU is connected to the distribution network intelligent analyzer for wireless communication, and the current temperature of the voltage divider resistor R5 is calculated through the built-in algorithm. After the high-voltage sampling voltage divider resistor R5 is overheated, a fault alarm message is sent and transmitted to the intelligent analyzer. The low-voltage sampling module is composed of a TMD3003 type AC voltage measurement module and a matching overcurrent protection circuit. The current sensor includes a high-voltage current sensor and a low-voltage secondary current clamp. The high-voltage sampling module and the high-voltage current sensor are connected to the distribution transformer terminal through a high-voltage measuring rod, and the low-voltage sampling module and the low-voltage secondary current clamp are connected to the distribution transformer terminal through a low-voltage measuring clamp.

[0017] In this embodiment, the distribution network intelligent analyzer is a PC. After receiving the high voltage, high current, low voltage, and low voltage current data wirelessly transmitted by the voltage sampling module and the current sensor, it can realize online distribution transformer operation gear calculation, impedance calculation, three-phase imbalance test, and provide operation and maintenance opinions and gear adjustment strategies. Specifically, the intelligent analyzer is used for online measurement of distribution transformer gears. According to the set voltage divider ratio, the average value of multiple high-voltage side line voltages is compared with the average value of multiple measurements on the low-voltage side, which is the current distribution transformer operation ratio. The ratio is compared with the standard gear ratios of the system distribution transformer, and the current system gear can be calculated. The intelligent analyzer is used for distribution transformer gear management strategy. According to the online measurement of the low-voltage side voltage value of the distribution transformer gear, it is compared with the system standard output voltage value. If the low-voltage side voltage is low, it should be upgraded. If the low-voltage side voltage is high, it should be downgraded. Combined with the past measurement data of the station, the appropriate operation gear strategy of the distribution transformer of the station is given. The intelligent analyzer is used for distribution transformer impedance calculation. It can calculate the input and output impedance of the transformer according to the measured high-voltage side voltage and current ratio and the low-voltage side voltage and current ratio, which is an important basis for transformer fault judgment. The intelligent analyzer is used for power quality analysis. According to the measured three-phase voltage and current, it can be judged whether there is a difference between the phases. If the difference is large, it can be determined that the three phases are unbalanced and need to be repaired. The high-voltage measuring rod and the low-voltage measuring clamp are provided with multiple layers of insurance insulation layers on the outside to ensure the safety of the operator when taking power and connecting. At the same time, the high-voltage measuring rod is a retractable rod. The voltage sampling module and the current sensor have built-in rechargeable batteries, and there is no need to take power on site to avoid interference with the voltage signal on site. The present application provides a distribution transformer operation gear operation and maintenance device. First, the required high-precision high-voltage side voltage and current signals can be obtained through the high-voltage measuring rod, and the low-voltage side voltage and current signals are collected using the low-voltage measuring end. The collected signals are transmitted to the intelligent control analyzer through the wireless Lora transmission device, and the current operating gear of the distribution transformer is calculated according to the data, and the current distribution transformer gear operation and maintenance opinions are given. The device can also calculate the impedance of the current distribution transformer and perform intelligent analysis on the power quality of the current distribution transformer station through three-phase unbalance test. At the same time, the device transmits the current sampling data and test results to the power grid service end through wireless encryption equipment, so that the background can collect the comprehensive operation status of the distribution transformer and provide intelligent maintenance solutions for the long-term stable operation of the distribution transformer station in the future.

[0018] The embodiments described above are merely descriptions of preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the protection scope determined by the claims of the present invention.

Claims

1. A distribution transformer operating gear operation and maintenance device, comprising a distribution network intelligent analyzer, the distribution network intelligent analyzer is connected to a power grid service end via a wireless encryption remote transmission device, and is characterized in that: The distribution network intelligent analyzer is connected to a voltage sampling module and a current sensor for obtaining measurement data through a wireless transmission module. The voltage sampling module includes a high-voltage sampling module and a low-voltage sampling module. The high-voltage sampling module can convert a 10kV high voltage into a 0-3.3V voltage signal through the resistor voltage division principle. The high-voltage sampling module is provided with an AD digital conversion sampling circuit. The sampling circuit is provided with a low-voltage voltage dividing resistor R5. Voltage dividing resistors R1, R2, R3 and R4 are provided between R5 and the high-voltage line at the end of the distribution transformer. Control switches S1, S2, S3 and S4 are correspondingly provided on each voltage dividing resistor; a temperature detection circuit is also provided near R5; the low-voltage sampling module is composed of a TMD3003 AC voltage measurement module and a matching overcurrent protection circuit, the current sensor includes a high-voltage current sensor and a low-voltage secondary current clamp, the high-voltage voltage sampling module and the high-voltage current sensor are connected to the end of the distribution transformer through a high-voltage measuring rod, and the low-voltage voltage sampling module and the low-voltage secondary current clamp are connected to the low-voltage side of the distribution transformer through a low-voltage measuring clamp.

2. A distribution transformer operating gear operation and maintenance device according to claim 1, characterized in that: The temperature detection circuit comprises a thermistor PT100, a resistor R7 is arranged in parallel on the PT100, a voltage-dividing resistor R6 is connected to R7, an embedded chip MCU is connected to R7, and the MCU is communicatively connected with a distribution network intelligent analyzer.

3. The distribution transformer operating gear operation and maintenance device according to claim 1, characterized in that: The wireless transmission module is a Lora communication module, and the communication chip is Semtech SX127x.

4. The distribution transformer operating gear operation and maintenance device according to claim 1, characterized in that: The distribution network intelligent analyzer is a PC that can perform distribution transformer operation gear calculation, impedance calculation, and three-phase unbalance test.

5. The distribution transformer operating gear operation and maintenance device according to claim 1, characterized in that: Multiple layers of safety insulation layers are arranged outside the high-voltage measuring rod and the low-voltage measuring clamp.

6. The distribution transformer operating gear operation and maintenance device according to claim 1, characterized in that: The voltage sampling module and current sensor have built-in rechargeable batteries and do not require on-site power supply.

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