CN103115690A - Method of online monitoring for high-voltage switch contact temperature rise - Google Patents

Abstract

An on-line monitoring method for temperature rise of high-voltage switch contacts, the equipment used includes a transmitting part power supply circuit, a temperature acquisition circuit, a transmitting part microprocessor, a wireless transmitting circuit, a wireless receiving circuit, a receiving part microprocessor, a display circuit and a receiving part power circuit. The power supply circuit of the transmitting part includes a current induction coil and a ring-shaped iron core. The iron core is set on the conductor of the switch contact to be tested, and the induced current of the current induction coil is used to provide power for the temperature acquisition circuit, the microprocessor of the transmitting part and the wireless transmitting circuit. . The temperature signal collected by the temperature acquisition circuit is processed by the microprocessor and then transmitted by the wireless transmitting circuit, received by the wireless receiving circuit, and then processed by the microprocessor and then displayed by the display circuit to display the measured temperature of the switch contact. When the temperature rise exceeds the set When the upper limit value is exceeded, an alarm signal will be issued, which can effectively monitor the failure of the high-voltage switch contact and ensure the safe operation of the power system.

Description

A method for on-line monitoring of temperature rise of high-voltage switch contacts

technical field

The invention relates to a circuit and a method for monitoring the temperature rise of a high-voltage switch contact on-line by using wireless radio frequency technology, and then diagnosing the failure of the high-voltage switch contact to ensure the safe operation of a power system. the

Background technique

In order to ensure the safe operation of the power system, the diagnosis of thermal faults in the power system is generally valued by people. When the high-voltage bus is overloaded or the contact of the high-voltage switch is not in good contact, the contact resistance will become larger and heat will be generated when the load current flows. , This heating phenomenon causes insulation aging or even breakdown, thereby causing a short circuit, forming a major accident, and causing major economic losses.

In the power supply system using power cables for power transmission and distribution, statistics show that more than 90% of cable failures are caused by joint failures, and joint contact resistance increases, overload, etc. cause joint temperature to be too high, which is the main cause of failure. reason. According to the survey and statistics of Beijing Electric Power Research Institute, temperature rise faults accounted for 8.9% of the distribution voltage level switch accidents in China's power system throughout the 1990s. It is of great significance to the safe and reliable operation of the power system to eliminate the hidden dangers of thermal faults.

According to whether the sensor and the measured object are in contact or not, the research on this technology at home and abroad is divided into two methods: contact temperature measurement and non-contact temperature measurement. The non-contact temperature measurement method adopts thermal infrared detection technology, which is made according to the certain functional relationship between the relative radiation intensity and temperature of the object. Its advantages are large measurement range and high accuracy, but in practical applications due to There are great limitations due to the limitation of the angle of view and the distance coefficient of the instrument itself. Another disadvantage of the infrared thermometer is that it needs manual inspection, and sometimes it is affected by factors such as weather. It cannot detect the high voltage enclosed in the cabinet. Switch contacts cannot realize the integrated integration of high-voltage equipment and online temperature detection. There are many contact temperature measurement methods, mainly as follows: (1) color temperature film method, using color film (also known as temperature recording label), which undergoes a series of chemical and physical changes after being heated, from the change of molecular structure, The color of the reflected light changes, and the temperature can be judged according to its color. The disadvantage is that the accuracy is low, the reliability is poor, and quantitative measurement cannot be performed. Moreover, for high-voltage switch contacts, etc., the color is almost invisible when running in a closed cabinet. (2) Optical fiber temperature measurement technology. With the support of the American Electric Power Research Institute (EPRI), Luke Corporation of the United States has developed a fluorescent optical fiber temperature measurement device specially developed and produced for power system applications to monitor the temperature of transformer windings. Brand-new on-line monitoring technology for internal temperature of high-voltage electrical equipment. Optical fiber has good electrical insulation performance and anti-electromagnetic interference ability. At the same time, the probe can be buried in a high-voltage selected part inside the power equipment to directly measure the actual temperature change at that point. However, the fiber optic thermometer is expensive, and the installation and transformation of the fiber optic thermometer is troublesome. After long-term operation, the insulation of the fiber is aging, causing mutual breakdown between the high and low voltage sides. The fiber optic temperature measurement technology has not yet been popularized in China; (3) Others Contact temperature measurement: There have also been a variety of online contact temperature measurement solutions in China. The main method is to install the temperature sensor on the switch contact, and send the temperature signal to the ground through radio frequency technology or light intensity modulation technology, and then the ground computer controls the temperature. The temperature signal is processed. These solutions all have the problem of how to supply power to the temperature sensor without exception. There are usually the following power supply methods (1) Battery method: the biggest disadvantage is that it cannot guarantee normal power supply during the entire high-voltage side non-maintenance period; (2) ) Photocell method: the high-voltage side sensor uses silicon photocells, and the light source is provided by the low-voltage side of the ground, so that the sensor is powered on. The disadvantage is that it is not easy to install and the interphase insulation of the high-voltage side is affected by the large area of the silicon photocell after installation; (3) The low-voltage side power supply : The disadvantage is that there is a potential for mutual feed and breakdown between the low-voltage side and the high-voltage side.

Contents of the invention

The technical problem to be solved by the present invention is to provide a device for on-line monitoring of the temperature rise of the contacts of the high-voltage switch, which does not require an external power supply, but uses the large current flowing through the high-voltage switch to obtain power supply power through electromagnetic coupling. The radio frequency technology further diagnoses the faults of the high-voltage switch contacts to ensure the safe operation of the power system.

To achieve the above purpose, the technical solution adopted is:

An online monitoring method for temperature rise of high-voltage switch contacts, characterized in that:

1. The equipment used is a high-voltage switch contact temperature rise online monitoring device of the present invention, which includes a transmitting part power supply circuit, a temperature acquisition circuit, a transmitting part microprocessor, a wireless transmitting circuit, a wireless receiving circuit, and a receiving part. device, the display circuit of the receiving part and the power supply circuit of the receiving part.

The power supply circuit of the transmitting part is composed of a current induction coil, a ring iron core and a voltage conversion module.

The current induction coil is wound on the annular iron core. The specific number of turns should be determined according to the measured current value in a certain proportion. The two leads of the current induction coil are connected to the corresponding terminals of the voltage conversion module. The voltage conversion module is rectification, filtering, Regulator circuit module. The voltage output terminal of the voltage conversion module is respectively connected with the temperature acquisition circuit, the microprocessor of the transmitting part and the voltage input terminal of the wireless transmitting circuit.

The temperature signal output terminal of the temperature acquisition circuit is connected with the temperature signal input interface of the microprocessor of the transmitting part; the signal output terminal of the microprocessor of the transmitting part is connected with the signal input terminal of the wireless transmitting circuit.

The power supply circuit of the receiving part is a rectification, filtering and voltage stabilizing circuit, which is powered by an AC power supply or directly by a battery, and provides power for the wireless receiving circuit, the receiving part microprocessor and the display circuit of the receiving part. The temperature signal output end of the wireless receiving circuit is connected with the temperature signal input end of the microprocessor of the receiving part, and the temperature signal output end of the microprocessor of the receiving part is connected with the corresponding interface of the display circuit of the receiving part.

The temperature acquisition in the temperature acquisition circuit can be completed by digital temperature sensors AD590, LM92, or thermistors (such as 10KΩ, 35KΩ); the microprocessor of the transmitting part and the microprocessor of the receiving part can be PIC, NSP430, 51 or For AVR series, etc., the wireless transmitting and receiving radio frequencies of the wireless transmitting circuit and wireless receiving circuit are in the range of 315-960MHZ, and the integrated module MAX1479, MAX7030 or MAX7031 is selected; the high-voltage temperature monitoring terminal and the display instrument terminal are completely isolated by wireless technology. , The microprocessor in the receiving part has wireless (GPRS) and wired (485 or 232) interface circuits.

2. On-line monitoring method of high voltage switch contact temperature rise:

Seal the ring-shaped iron core with insulating material and put it on the conductor of the switch contact to be tested. In this way, when the high-voltage contact passes through the current, the current induction coil will couple the large current flowing through the switch contact, and the current induction coil will output The two lead wires at the terminal are connected to the voltage conversion module to provide power for the temperature acquisition circuit, the transmitting part of the microprocessor and the wireless transmitting circuit. Obtain energy to provide electric energy for the collector, which solves the problem that the traditional battery power supply is difficult to replace and sometimes cannot be replaced. At the same time, due to the use of small CT and magnetic saturation technology, the power supply circuit of the transmitting part has achieved a wide current range. 50A-5000A can provide stable voltage. The temperature acquisition circuit realizes temperature acquisition through a digital temperature sensor or a thermistor. The temperature acquisition circuit sends the collected temperature signal of the contact point to the transmitting part of the microprocessor for processing, and the transmitting part of the microprocessor processes the processed temperature signal. After modulation, it is sent to the wireless transmission circuit. The wireless transmission adopts the open frequency band micro-power transmission, which will not interfere with other equipment. At the same time, the high-voltage temperature monitoring terminal is completely isolated from the display instrument terminal. After the wireless receiving circuit demodulates the received temperature signal It is sent to the microprocessor of the receiving part for processing, and the microprocessor of the receiving part sends the processed temperature value to the display circuit of the receiving part for display. The high-voltage switch contact temperature rise online monitoring circuit based on wireless radio frequency technology is used in the temperature acquisition part. Epoxy resin is poured into different specifications of fixture kits to apply different specifications of contact switches (such as round contacts or flat contacts).

The present invention has positive effects: (1) In the high-voltage switch contact temperature rise online monitoring circuit based on wireless radio frequency technology of the present invention, small CT and magnetic saturation technology are used to realize a wide current range of 50A- 5000A can provide stable working voltage. (2) The wireless transmission of the high-voltage switch contact temperature rise online monitoring circuit based on wireless radio frequency technology adopts open frequency band micro-power transmission, which will not interfere with other equipment, and at the same time realizes the complete isolation of the high-voltage temperature monitoring terminal and the display instrument terminal. (3) In the high-voltage switch contact temperature rise online monitoring circuit based on wireless radio frequency technology of the present invention, the temperature acquisition part is poured in different specifications of fixture kits to be suitable for different specifications of contact switches (such as round contacts or flat contacts) .

Description of drawings

FIG. 1 is a schematic diagram of the temperature acquisition part of Embodiment 1.

FIG. 2 is a schematic diagram of the temperature display part of Embodiment 1. FIG.

FIG. 3 is a schematic diagram of the power supply circuit of the transmitting part in Embodiment 1. FIG.

Detailed ways

An online monitoring method for temperature rise of high-voltage switch contacts, characterized in that:

1. The online monitoring equipment used is an online monitoring device for the temperature rise of high-voltage switch contacts, including the power supply circuit 1 of the transmitting part, the temperature acquisition circuit 2, the microprocessor of the transmitting part 3, the wireless transmitting circuit 4, the wireless receiving circuit 5, and the receiving part. The microprocessor 6, the display circuit 7 of the receiving part and the power supply circuit 8 of the receiving part.

The power supply circuit 1 of the transmitting part is composed of a current induction coil 9, an annular iron core 10 and a voltage conversion module 11. The current induction coil 9 is wound on the annular iron core 10, and the two leads of the current induction coil 9 correspond to the voltage conversion module 11. The connection terminal is connected, and the voltage output end of the voltage conversion module 11 is respectively connected with the voltage input end of the temperature acquisition circuit 2 , the transmitting part microprocessor 3 and the wireless transmitting circuit 4 . The temperature signal output end of the temperature acquisition circuit 2 is connected with the temperature signal input interface of the microprocessor 3 of the transmitting part. The temperature signal output end of the microprocessor 3 of the transmitting part is connected with the signal input interface of the wireless transmitting circuit 4 .

The voltage output end of the power supply circuit 8 of the receiving part is respectively connected with the voltage input interfaces of the wireless receiving circuit 5 , the microprocessor 6 of the receiving part and the display circuit 7 of the receiving part. The temperature signal output end of the wireless receiving circuit 5 is connected with the temperature signal input interface of the microprocessor 6 of the receiving part, and the temperature signal output end of the microprocessor 6 of the receiving part is connected with the signal input interface of the display circuit 7 of the receiving part.

2. On-line monitoring of temperature rise of high-voltage switch contacts:

The annular iron core 10 is sealed with an insulating material and fitted on the conductor 12 of the switch contact under test. The current induction coil 9 couples the current flowing through the switch contact under test, and the current induction coil 9 passes through the voltage conversion module 11 respectively for temperature The acquisition circuit 2, the microprocessor 3 of the transmitting part and the wireless transmitting circuit 4 provide a regulated power supply with a current range of 50A-5000A, and the power supply circuit of the transmitting part can also charge the backup battery. The temperature signal collected by the temperature acquisition circuit 2 is sent to the transmitting part microprocessor 3 for processing, and the transmitting part microprocessor 3 modulates the processed temperature signal to the wireless transmitting circuit 4, and the wireless receiving circuit 5 receives the wireless transmitting circuit 4 The temperature signal sent out is demodulated and then sent to the microprocessor 6 of the receiving part for processing, and the processed temperature signal is sent to the display 7 of the receiving part for display in real time, and the online monitoring of the temperature rise of the high-voltage switch contact is completed.

The temperature acquisition in the temperature acquisition circuit is completed by a digital temperature sensor AD590 or LM92, or by a thermistor 10KΩ or 35KΩ; the microprocessor in the transmitting part and the microprocessor in the receiving part use PIC, NSP430, 51 or AVR, and the wireless transmitting circuit The radio frequency of the wireless transmission and wireless reception of the wireless receiving circuit is in the range of 315-960MHz, and the integrated module MAX1479, MAX7030 or MAX7031 is selected; the high-voltage temperature monitoring terminal and the display instrument terminal are completely isolated by wireless technology, and the microprocessor of the receiving part There are wireless GPRS interface circuit and wired 485 or 232 interface circuit.

Claims (1)

1. A method for on-line monitoring of high-voltage switch contact temperature rise, characterized in that: ①. The online monitoring equipment used is an online monitoring device for the temperature rise of high-voltage switch contacts, including the power supply circuit of the transmitting part (1), the temperature acquisition circuit (2), the microprocessor of the transmitting part (3), the wireless transmitting circuit (4), Wireless receiving circuit (5), microprocessor of receiving part (6), display circuit of receiving part (7) and power supply circuit of receiving part (8); The power supply circuit (1) of the transmitting part is composed of a current induction coil (9), an annular iron core (10) and a voltage conversion module (11). The current induction coil (9) is wound on the annular iron core (10), and the current induction coil The two leads of (9) are connected to the corresponding terminals of the voltage conversion module (11), and the voltage output terminals of the voltage conversion module (11) are respectively connected to the temperature acquisition circuit (2), the microprocessor of the transmitting part (3) and the wireless transmitter The voltage input terminal of the circuit (4) is connected, the temperature signal output terminal of the temperature acquisition circuit (2) is connected to the temperature signal input interface of the microprocessor (3) of the transmitting part, and the temperature signal of the microprocessor (3) of the transmitting part The output end is connected to the signal input interface of the wireless transmitting circuit (4); The voltage output terminals of the power supply circuit (8) of the receiving part are respectively connected to the voltage input interfaces of the wireless receiving circuit (5), the microprocessor (6) of the receiving part and the display circuit (7) of the receiving part, and the wireless receiving circuit (5) The temperature signal output end of the receiving part is connected to the temperature signal input interface of the microprocessor (6) of the receiving part, and the temperature signal output end of the microprocessor (6) of the receiving part is connected to the signal input interface of the display circuit 7 of the receiving part; ②. On-line monitoring of temperature rise of high-voltage switch contacts: The annular iron core (10) is sealed with an insulating material and placed on the conductor (12) of the switch contact under test. The current induction coil (9) couples the current flowing through the switch contact under test, and the current induction coil (9) The voltage conversion module (11) provides regulated power supplies for the temperature acquisition circuit (2), the microprocessor (3) of the transmitting part and the wireless transmitting circuit (4) respectively, and the current range is 50A-5000A. It can charge the backup battery, and the temperature signal collected by the temperature acquisition circuit (2) is sent to the transmitting part of the microprocessor (3) for processing, and the transmitting part of the microprocessor (3) modulates the processed temperature signal and sends it to the wireless transmitter The circuit (4), the wireless receiving circuit (5) receives the temperature signal sent by the wireless transmitting circuit (4), demodulates it and sends it to the microprocessor (6) in the receiving part for processing, and sends the processed temperature signal to the The display (7) of the receiving part displays and completes the online monitoring of the temperature rise of the high-voltage switch contacts; The temperature acquisition in the temperature acquisition circuit is completed by a digital temperature sensor AD590 or LM92, or by a thermistor 10KΩ or 35KΩ; the microprocessor in the transmitting part and the microprocessor in the receiving part use PIC, NSP430, 51 or AVR, and the wireless transmitting circuit The radio frequency of the wireless transmission and wireless reception of the wireless receiving circuit is in the range of 315-960MHz, and the integrated module MAX1479, MAX7030 or MAX7031 is selected; the high-voltage temperature monitoring terminal and the display instrument terminal are completely isolated by wireless technology, and the microprocessor of the receiving part There are wireless GPRS interface circuit and wired 485 or 232 interface circuit.

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