CN103604507B - A kind of method for on-line monitoring GIS tank interior temperature rise of conductor - Google Patents

Abstract

The invention provides a method for on-line monitoring the temperature rise of the conductor inside the GIS tank body. The infrared sensor is used to receive the infrared radiation emitted by the temperature rise part, and the infrared energy is converted into an electrical signal. After passing through the amplifier, the signal processing circuit and the AD conversion circuit, Convert it to the radiation power of the conductor, and then calculate the absolute temperature of the conductor through Stephen-Boltzmann's law, and finally correct the absolute temperature to obtain an accurate absolute temperature of the conductor. The invention is used to monitor the temperature rise of the inner conductor of the GIS in real time under the condition of electrified operation, so as to avoid the occurrence of accidents.

Description

A method for on-line monitoring the temperature rise of the conductor inside the GIS tank

technical field

The invention relates to a monitoring method, in particular to a method for online monitoring the temperature rise of a conductor inside a GIS tank body.

Background technique

Any object above absolute zero will emit energy in the form of electromagnetic waves. This energy is called radiant energy. The thermal effect of electromagnetic waves in the infrared short-wave part with a wavelength of 0.76-40 μm is the most obvious. Therefore, the infrared sensor can be used to measure the temperature of the temperature rising part by receiving the infrared rays emitted by the heating part.

At present, there are existing methods for GIS temperature measurement in the industry, mainly through the transformation of the local material of the GIS conductor to increase the emissivity of the conductor surface, and then use the infrared sensor to receive infrared measurement of temperature. A live GIS does not apply.

Compared with conventional electrical appliances, gas-insulated metal-enclosed switchgear (GIS) has the advantages of small footprint, high reliability, less maintenance and long service life in terms of structural performance, and has been widely used in domestic and foreign power systems. The survey shows that due to the lack of strict quality control in various links such as factory assembly, on-site installation, and handover acceptance, the internal conductor plugging parts of GIS equipment are overheated or even burned due to poor contact, which seriously affects the reliability of power grid power supply.

As an important means of power system fault diagnosis, temperature monitoring is beneficial to discover the initial faults of GIS equipment, prevent accidents from expanding, and provide guarantee for the normal operation of GIS equipment. Excessive GIS load current, loose connection parts, poor contact, or improper closing of the switch may cause excessive temperature rise of conductive parts. For example: during normal operation, the GIS conductive circuit generates heat energy through the working current for a long time, so that the temperature of the electrical material will rise, generally not exceeding the specified value, but once the conductive circuit is unreliable, the contact resistance will increase significantly, making the electrical material If the temperature rises beyond the specified value, the mechanical strength or physical properties of electrical materials will decrease, and in severe cases, the contact parts will be melted, and even breakdown and discharge failures will occur. Since GIS is a fully enclosed device, the temperature of conductive parts cannot be detected by conventional temperature measurement methods. Therefore, it is of great significance to study the online monitoring of GIS temperature to find the internal overheating phenomenon of GIS and avoid equipment failure.

For poor contact defects of conductors, methods such as measuring loop resistance and partial discharge monitoring are usually used at the operation site. However, measuring GIS loop resistance requires a power outage, and generally the GIS busbar is long. Due to the power limit of the test instrument, only obvious defects of poor contact can usually be detected. . At present, there is still a lack of effective fault criteria for partial discharge monitoring, and the corresponding relationship between overheating and partial discharge needs to be further studied. In addition, some manufacturers at home and abroad use methods such as thermistors and optical fiber sensors to measure temperature, but they are mostly used in high-voltage switchgear. For example, ABB uses quartz temperature sensors to monitor the temperature rise of switchgear busbars in real time. Since GIS is a fully enclosed device, there are many technical problems that are still difficult to solve, such as the internal insulation performance of the embedded thermistor or optical fiber sensor, the sealing method of the optical fiber outlet interface, and the service life of the sensor. Realize field application.

Contents of the invention

In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides a method for online monitoring of the temperature rise of the conductor inside the GIS tank, using an infrared sensor to receive the infrared rays emitted by the temperature rise part, and convert the infrared energy into an electrical signal, which is passed through the amplifier , signal processing circuit and AD conversion circuit, transform it into the radiated power of the conductor, and then calculate the absolute temperature of the conductor through the Stephen-Boltzmann law, and finally correct the absolute temperature to obtain the accurate absolute temperature of the conductor. The invention is used to monitor the temperature rise of the inner conductor of the GIS in real time under the condition of electrified operation, so as to avoid the occurrence of accidents.

In order to realize the above-mentioned purpose of the invention, the present invention takes the following technical solutions:

The invention provides a method for on-line monitoring the temperature rise of a conductor inside a GIS tank, comprising the following steps:

Step 1: Determine the emissivity of the conductor inside the GIS tank;

Step 2: monitoring the radiation power of the conductor, and calculating the absolute temperature of the conductor;

Step 3: Correct the absolute temperature of the conductor.

Described step 1 comprises the following steps:

Step 1-1: Adjust the emissivity line of the contact temperature sensor to 1;

Step 1-2: keeping the conductor at a constant temperature, and sticking the contact temperature sensor on the conductor;

Step 1-3: using the contact temperature sensor to measure the _temperature standard value T of the conductor;

Steps 1-4: Use an infrared thermometer to measure the current measured _temperature value T of the conductor;

Step 1-5: Calculate the emissivity of the conductor, the emissivity is represented by ε, there are:

In the step 2, the sampling infrared sensor monitors the radiation power of the conductor, which specifically includes the following steps:

Step 2-1: Install infrared glass on the GIS tank;

Step 2-2: The infrared rays emitted by the conductor pass through the infrared glass and enter the infrared sensor;

Step 2-3: the infrared sensor monitors the radiation power of the conductor;

Step 2-4: Calculate the absolute temperature of the conductor.

The infrared glass is chalcogenide infrared glass.

In the step 2-3, the infrared sensor converts infrared rays into electrical signals, and the electrical signals pass through an amplifier and a signal processing circuit, and are converted into radiation power of the conductor through AD.

The distance between the infrared sensor and the conductor is greater than the distance between the inner wall of the GIS tank and the conductor.

In the step 2-4, the microprocessor chip in the infrared sensor calculates the absolute temperature of the conductor according to Stephen-Boltzmann's law, which has:

E＝εσT ⁴ (2)

Among them, T is the absolute temperature of the conductor, E is the radiation power of the conductor, and σ is the Stefan-Boltzmann constant.

In the step 3, the calculated absolute temperature T of the conductor is corrected by means of parameter fitting to obtain the final monitored value of the conductor temperature.

The material used in the GIS tank body is 0Cr13Al, which has a carbon content of 0.075%, a silicon content of 0.94%, a manganese content of 0.97%, a phosphorus content of 0.035%, a sulfur content of 0.025%, and a chromium content of 14.0%. Quantities are prepared from iron alloys, and the stated percentages are by weight.

Compared with prior art, the beneficial effect of the present invention is:

(1) Using this monitoring method does not require any modification to the interior of the GIS, and the detection method is safe and reliable;

(2) The measurement accuracy can be improved by adjusting the distance and angle between the infrared sensor and the temperature-measured part, and it is suitable for GIS equipment with different structures;

(3) By using this method, the heating defect of the conductor insertion part inside the GIS equipment can be found in real time;

(4) It is used to monitor the temperature rise of the internal conductor of GIS in real time under the condition of electrified operation, so as to avoid accidents.

Description of drawings

Fig. 1 is the flow chart of the method for on-line monitoring GIS tank internal conductor temperature rise;

Fig. 2 is a schematic diagram of monitoring the radiation power of a conductor by an infrared sensor;

Figure 3 is a schematic diagram of the installation structure of the infrared sensor and the GIS tank;

Among them, 1-metal flange, 2-infrared sensor, 3-infrared glass, 4-conductor insertion position.

detailed description

The present invention will be described in further detail below in conjunction with the accompanying drawings.

As shown in Fig. 1, the present invention provides a kind of method for on-line monitoring GIS tank interior conductor temperature rise, comprises the following steps:

Step 1: Determine the emissivity of the conductor inside the GIS tank;

Step 2: monitoring the radiation power of the conductor, and calculating the absolute temperature of the conductor;

Step 3: Correct the absolute temperature of the conductor.

The emissivity of a conductor is a physical quantity of the radiation ability of a conductor relative to a black body. It is not only related to the material shape, surface roughness, unevenness, etc. of the object, but also related to the direction of the test. If the conductor is a smooth surface, its directionality is more sensitive.

Described step 1 comprises the following steps:

Step 1-1: Adjust the emissivity line of the contact temperature sensor to 1;

Step 1-2: keeping the conductor at a constant temperature, and sticking the contact temperature sensor on the conductor;

Step 1-3: using the contact temperature sensor to measure the _temperature standard value T of the conductor;

Steps 1-4: Use an infrared thermometer to measure the current measured _temperature value T of the conductor;

Step 1-5: Calculate the emissivity of the conductor, the emissivity is represented by ε, there are:

In the step 2, the sampling infrared sensor monitors the radiation power of the conductor, which specifically includes the following steps:

Step 2-1: Install infrared glass on the GIS tank;

The infrared glass adopts chalcogenide infrared glass, which has good transmission performance in the infrared band of 1-17 μm, and fully meets the requirements of GIS infrared temperature measurement (the absolute temperature range of power equipment is 273K-473K, within this range, infrared The peak wavelength is 6.13-10.61 μm).

Step 2-2: The infrared rays emitted by the conductor pass through the infrared glass and enter the infrared sensor;

Step 2-3: the infrared sensor monitors the radiation power of the conductor;

Step 2-4: Calculate the absolute temperature of the conductor.

In the step 2-3, the infrared sensor converts infrared rays into electrical signals, and the electrical signals pass through an amplifier and a signal processing circuit, and are converted into radiation power of the conductor through AD.

The distance between the infrared sensor and the conductor is greater than the distance between the inner wall of the GIS tank and the conductor.

In the step 2-4, the microprocessor chip in the infrared sensor calculates the absolute temperature of the conductor according to Stephen-Boltzmann's law, which has:

E＝εσT ⁴ (2)

Among them, T is the absolute temperature of the conductor, E is the radiation power of the conductor, and σ is the Stefan-Boltzmann constant, which is taken as 5.67×10 ^-8 W/(m ² ·K ⁴ ).

Since the GIS equipment is filled with a certain pressure of SF ₆ gas during operation, the infrared rays will enter the temperature sensor after passing through the SF ₆ gas environment. Experiments have proved that the temperature rise errors of the parts measured by the temperature sensing system in different temperature ranges are different, which is related to the SF ₆ gas environment inside the GIS. The calculated absolute temperature T of the conductor is corrected by the method of parameter fitting to obtain the final conductor temperature monitoring value.

The material used in the GIS tank body is 0Cr13Al, which has a carbon content of 0.075%, a silicon content of 0.94%, a manganese content of 0.97%, a phosphorus content of 0.035%, a sulfur content of 0.025%, and a chromium content of 14.0%. Quantities are prepared from iron alloys, and the stated percentages are by weight. The GIS tank body can also be made of aluminum material.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the present invention can still be Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention shall be covered by the scope of the claims of the present invention.

Claims (1)

1. the method for on-line monitoring GIS tank interior temperature rise of conductor, it is characterised in that: described method includes following step Rapid:

Step 1: determine the emissivity of GIS tank interior conductor；

Step 2: monitor the radiant power of described conductor, and calculate the absolute temperature of conductor；

Step 3: revise the absolute temperature of conductor；

Described step 1 comprises the following steps:

Step 1-1: the emissivity line of contact temperature sensing sensor is adjusted to 1；

Step 1-2: described conductor is remained temperature constant state, and described contact temperature sensing sensor is attached on described conductor；

Step 1-3: use described contact temperature sensing sensor to measure the standard temperature T of conductor_{Standard temperature}；

Step 1-4: use infrared radiation thermometer to measure the temperature measured value T that conductor is current_{Temperature measured value}；

Step 1-5: calculate the emissivity of described conductor, emissivity ε represents, has:

In described step 2, the radiant power of described conductor monitored by sampling infrared sensor, specifically includes following steps:

Step 2-1: to GIS tank body installation infrared glass；

Step 2-2: the infrared ray that described conductor is launched enters described infrared sensor through described infrared glass；

Step 2-3: the radiant power of described conductor monitored by described infrared sensor；

Step 2-4: calculate the absolute temperature of conductor；

Described infrared glass uses chalcogenide infrared glass；

In described step 2-3, infrared ray is converted to the signal of telecommunication by described infrared sensor, and the described signal of telecommunication is through amplifier and letter Number process circuit, and through radiant power that AD conversion is described conductor；

The distance of described infrared sensor distance conductor is more than the distance of GIS inner tank wall distance conductor；

In described step 2-4, the micro-chip processor in described infrared sensor calculates conductor according to Stefan-Boltzman's law Absolute temperature, has:

E=ε σ T⁴ (2)

Wherein, T is the absolute temperature of conductor, and E is the radiant power of conductor, and σ is Stefan-Boltzmann constant；

In described step 3, by the method for parameter fitting, the absolute temperature T calculating conductor is modified, final to draw Conductor temperature monitor value；

Described GIS tank body use material be 0Cr13Al, its with carbon content be 0.075%, silicone content be 0.94%, Fe content Be 0.97%, phosphorus content be 0.035%, sulfur content be 0.025%, chromium content be 14.0%, surplus be prepared by the alloy of ferrum, institute The percent stated is percetage by weight.