High-voltage switch cabinet environment monitoring system and method

Abstract

The invention belongs to the technical field of switch cabinets, and relates to a high-voltage switch cabinet environment monitoring system and method. The method comprises the following steps: acquiring the temperature, the actual relative humidity, the ozone concentration, the oxygen concentration and the SF6 concentration in the high-voltage switch cabinet; setting a relative humidity expected value according to the obtained temperature; comparing the actual relative humidity with the expected value of the relative humidity, and if the actual relative humidity is greater than the expected value of the relative humidity, starting the fan module and adjusting the output voltage of the fan module until the actual relative humidity is equal to the expected value; and judging whether the high-voltage switch cabinet has a fault or not according to the ozone concentration, the oxygen concentration and the SF6 concentration. The PID control designed by the invention can adjust the control signal in real time according to the measurement deviation, so that the output of the controlled object is gradually close to the expected output, and the error is reduced; the system sensitivity can be improved, and humidity adjustment is achieved by rapidly adjusting the air volume; the PID has strong applicability, and can quickly respond to achieve an expected effect under different working conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field of switch cabinets, and in particular relates to a high-voltage switch cabinet environment monitoring system and method. Background Art

[0002] High-voltage switchgear is one of the main electrical equipment in the power system, and its voltage level generally ranges from 3.6kV to 550kV. The high-voltage switchgear consists of a cable room, a busbar room and a circuit breaker room. It mainly plays a role in disconnection in the power grid system's power generation, transmission, distribution and other energy conversion and consumption processes. It also has functions such as control and protection, and plays an important role in the safe, coordinated and reliable operation of the power system. According to incomplete statistics, every year many power plants and substations suffer huge economic losses due to high-voltage switchgear failures, which brings inconvenience to people's production and life. The reasons for high-voltage switchgear failure are as follows: (1) Circuit breaker failure Due to product quality and disrepair, the circuit breaker had problems such as polarity damage that was not discovered in time, poor sealing of the vacuum arc chamber and SF6 circuit breaker leakage, which led to an explosion during operation.

[0003] (2) Condensation in switch cabinet In the case of large temperature differences between day and night or rainy seasons, if there is no reliable dehumidification equipment in the switch room, the insulation parts inside the switch cabinet will be damp, causing condensation on the surface of the insulation parts. In addition, some substations will have water ingress into the cable trench. If the drainage is not timely and the sealing is not strict, the humidity in the switch cabinet will be too high, which will also cause condensation. In dry conditions, although there is dirt on the surface of the insulation parts, the resistance is very high and no flashover will occur. However, after being damp, the dielectric of the dirt layer gradually decomposes and forms a thin conductive liquid film on the insulation surface, which greatly reduces the insulation strength of the electrical equipment. If condensation occurs in the switch cabinet for a long time, verdigris will appear on the conductive parts, causing excessive contact resistance and heating, which can also easily lead to explosions.

[0004] The existing technology is to find problems through annual inspections, remove condensation and find circuit breaker failures through maintenance, and the problems are not found in time. Summary of the invention

[0005] The object of the present invention is to provide a high-voltage switch cabinet environment monitoring system and method, which solves the problem of switch cabinet condensation and circuit breaker fault early warning.

[0006] The present invention is achieved through the following technical solutions: The present invention discloses a method for monitoring the environment of a high-voltage switch cabinet, comprising: Obtain the temperature, actual relative humidity, ozone concentration, oxygen concentration and SF6 concentration in the high-voltage switchgear; Set the desired relative humidity value based on the obtained temperature; Compare the actual relative humidity with the expected relative humidity value. If the actual relative humidity is greater than the expected relative humidity value, start the fan module and adjust the output voltage of the fan module until the actual relative humidity is equal to the expected value. Determine whether the high-voltage switchgear is faulty based on the ozone concentration, oxygen concentration and SF6 concentration.

[0007] Furthermore, the output voltage of the fan module is adjusted. The specific algorithm is:

[0008] Among them, u(k) is the output voltage of the fan module at time k, is the proportionality coefficient, For the integration phase, is the differential coefficient, e(k) is the humidity deviation at time k, e(k-1) is the humidity deviation at time k-1, and k is the sampling time.

[0009] Furthermore, the calculation formula for humidity deviation is:

[0010] in, is the actual relative humidity collected at time k, is the expected value of relative humidity.

[0011] Furthermore, it is determined whether there is a fault in the high-voltage switch cabinet based on the ozone concentration, oxygen concentration and SF6 concentration. If there is a fault, an early warning is issued for the operating environment of the high-voltage switch cabinet; the environmental parameters inside the high-voltage switch cabinet are sent to a remote server for further judgment.

[0012] The present invention also discloses a high-voltage switch cabinet environment monitoring system, including a data acquisition module, a humidity judgment module, a voltage regulation module and a fault judgment module; A data acquisition module is used to obtain the temperature, actual relative humidity, ozone concentration, oxygen concentration and SF6 concentration in the high-voltage switch cabinet; The humidity judgment module is used to compare the actual relative humidity with the expected relative humidity value. If the actual relative humidity is greater than the expected value, the voltage regulation module and the fan module are started; the expected relative humidity value is set according to the obtained temperature; A voltage regulating module, used for adjusting the output voltage of the fan module until the actual relative humidity is equal to the expected value; The fault judgment module is used to judge whether there is a fault in the high-voltage switch cabinet according to the ozone concentration, oxygen concentration and SF6 concentration.

[0013] Furthermore, it also includes a sensor assembly, a data acquisition module, a communication module, a host, and a wind model module installed in a high-voltage switch cabinet; The sensor components include temperature and humidity sensors, ozone sensors, oxygen sensors and SF6 sensors installed in the busbar room; temperature and humidity sensors installed in the trolley room, cable room and instrument room; The sensor component is connected to the data acquisition module, and the data acquisition module is connected to the host through the communication module; The host is provided with a data acquisition module, a humidity judgment module, a voltage regulation module and a fault judgment module.

[0014] Furthermore, the algorithm stored in the voltage regulation module is:

[0015] Among them, u(k) is the output voltage of the fan module at time k, is the proportionality coefficient, For the integration phase, is the differential coefficient, e(k) is the humidity deviation at time k, e(k-1) is the humidity deviation at time k-1, and k is the sampling time.

[0016] Furthermore, the calculation formula for humidity deviation is:

[0017] in, is the actual relative humidity collected at time k is the expected value of relative humidity.

[0018] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention discloses a high-voltage switch cabinet environment monitoring system and method. The existing technology is to find problems through annual inspections and remove condensation through maintenance. The present invention directly destroys the conditions for condensation generation. It also monitors the SF6 of the circuit breaker fault and detects gases such as oxygen and ozone in the high-voltage switch cabinet, indirectly judging partial discharge and the working environment of the switch cabinet.

[0019] The present invention installs temperature and humidity sensors in the busbar room, trolley room, cable room and instrument room to monitor the changes in temperature and humidity in the high-voltage switch in real time. When the humidity in the switch cabinet may reach the condensation condition, the host controls the fan module to adjust the humidity in the switch cabinet, so that the switch cabinet works in a safe working environment.

[0020] The essence of regulating voltage is to regulate air volume. The PID control designed in the present invention can adjust the control signal in real time according to the measurement deviation, so that the output of the controlled object gradually approaches the expected output and reduces the error. It can also improve the system sensitivity and quickly adjust the air volume to achieve humidity regulation. PID has strong applicability and can respond quickly under different working conditions to achieve the expected effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of the principle of a high-voltage switch cabinet environment monitoring system of the present invention; Figure 2 This is a schematic diagram of the process in which the host adjusts the output voltage of the fan module according to the humidity signal. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present invention more clear, the following is further described in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the embodiments described are only part of the embodiments of the present invention, not all embodiments.

[0023] The components described and shown in the drawings and embodiments of the present invention may be arranged and designed in various configurations. Therefore, the detailed description of the embodiments of the present invention provided in the following drawings is not intended to limit the scope of the claimed invention, but merely represents a selected embodiment of the present invention. Based on the drawings and embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0024] The present invention discloses a high-voltage switch cabinet environment monitoring system, comprising a data acquisition module, a humidity judgment module, a voltage regulation module and a fault judgment module; A data acquisition module is used to obtain the temperature, actual relative humidity, ozone concentration, oxygen concentration and SF6 concentration in the high-voltage switch cabinet; The humidity judgment module is used to compare the actual relative humidity with the expected relative humidity value. If the actual relative humidity is greater than the expected relative humidity value, the voltage regulation module and the fan module are started; the expected relative humidity value is set according to the acquired temperature; A voltage regulating module, used for adjusting the output voltage of the fan module until the actual relative humidity is equal to the expected value; The fault judgment module is used to judge whether there is a fault in the high-voltage switch cabinet according to the ozone concentration, oxygen concentration and SF6 concentration.

[0025] Specifically, Figure 1 As shown, the high-voltage switch cabinet environment monitoring system also includes a sensor component, a data acquisition module, a communication module, a host, and a wind model module installed in the high-voltage switch cabinet; The sensor components include temperature and humidity sensors, ozone sensors, oxygen sensors and SF6 sensors installed in the busbar room; temperature and humidity sensors installed in the trolley room, cable room and instrument room; The sensor component is connected to the data acquisition module, and the data acquisition module is connected to the host through the communication module; The host is connected with the dehumidification device and the fan module; The host is equipped with a data acquisition module, a humidity judgment module, a voltage regulation module and a fault judgment module; When the humidity signal is not within a preset range, the fan module is started; and the output voltage of the fan module is adjusted according to the humidity signal.

[0026] Temperature and humidity sensors monitor the temperature and humidity of each part of the high-voltage switchgear in real time. Ozone sensors, oxygen sensors, and SF6 sensors are used to collect busbar indoor environmental parameters.

[0027] Under the same water vapor content, the relative humidity decreases when the temperature increases and increases when the temperature decreases. The expected relative humidity can be adjusted appropriately according to the temperature change.

[0028] The actual relative humidity collected continuously is The expected relative humidity is , the relative humidity deviation is , t represents time, then:

[0029] The fan module can adjust the air volume through voltage, and the host can use PID method to adjust the fan. The host controls the output voltage according to the relative humidity deviation. The specific relationship is: (1) in, is the output voltage, is the relative humidity error, is the proportionality coefficient, is the integration coefficient, is the differential coefficient.

[0030] Since there is a certain lag in temperature and humidity control, if only proportional control is used, the voltage regulation system will cause oscillation, and an integral link is needed to adjust the humidity deviation. When it is desired to adjust the deviation, it can be achieved through a differential link.

[0031] When software control is used, the humidity deviation is:

[0032] in, is the actual relative humidity collected at time k, is the expected value of relative humidity. The expected value of relative humidity needs to be set according to the collected temperature.

[0033] Discretize formula (1), as Figure 2 As shown, it is expressed as: (2) Among them, u(k) is the output voltage of the fan module at time k, is the proportionality coefficient, For the integration phase, is the differential coefficient, e(k) is the humidity deviation at time k, e(k-1) is the humidity deviation at time k-1, and k is the sampling time.

[0034] PID parameter adjustment is the core of voltage regulation, so it is necessary to determine the parameters beforehand. , Parameters, according to the following steps: (1) Close the integral and differential links and increase make Oscillates, varying between positive and negative values.

[0035] (2) Reduction , when e Relatively stable, fluctuating within a small range, .

[0036] (3) Increase ki so that the actual discrete relative humidity is and the desired relative humidity is Almost equal, that is Approximately equal to 0, determine ki.

[0037] (4) The larger the kd, the faster the humidity adjustment speed. The faster the speed is, the faster it is. , determine the initial , adjust kd so that the target humidity is stable within the specified time. Kd is adjusted according to the specific adjustment speed requirements.

[0038] In addition, the data acquisition module also collects ozone, oxygen, SF6 and other gases in the busbar room to provide early warning of the operating environment of the high-voltage switchgear. The principle is as follows: The gas composition in the normal atmosphere is relatively stable. Calculated by volume fraction: nitrogen accounts for about 78%, oxygen accounts for about 21%, rare gases account for about 0.94% (helium He, neon Ne, argon Ar, krypton Kr, xenon Xe, radon Rn), carbon dioxide accounts for about 0.03%, and other gases and impurities account for about 0.03%, such as ozone, nitric oxide, nitrogen dioxide, water vapor, etc. However, the air in the high-voltage switchgear is different due to the effect of the electric field. Charged particles gain higher energy under the action of the electric field, collide violently with the oxygen in the air, break its molecular bonds, and ionize oxygen atoms.

[0039] These oxygen atoms diffuse to the surroundings and react chemically with oxygen to produce ozone

[0040] In the formula, e is an electron and M is other gas molecules, such as nitrogen, carbon dioxide gas molecules, etc.

[0041] Ozone has extremely poor stability at normal temperature and pressure. The half-life of ozone decomposition in the air at a content of less than 1% is about 20 to 30 minutes.

[0042]

[0043] Under normal conditions, the above process in the switch cabinet will reach a balance, that is, the ozone concentration will remain constant at a low level. If the electric field is concentrated, the partial discharge is aggravated, there is significant creepage, or the insulation medium is in the early stage of breakdown due to some reason, the above process of ionizing oxygen atoms and synthesizing ozone will be more intense, and the ozone concentration in the cabinet will reach a new balance at a higher level or continue to rise until the insulation breaks down.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for monitoring the environment of a high-voltage switch cabinet, characterized in that: include: Obtain the temperature, actual relative humidity, ozone concentration, oxygen concentration and SF6 concentration in the high-voltage switchgear; Set the desired relative humidity value based on the obtained temperature; Compare the actual relative humidity with the expected relative humidity value. If the actual relative humidity is greater than the expected relative humidity value, start the fan module and adjust the output voltage of the fan module until the actual relative humidity is equal to the expected value. Determine whether the high-voltage switchgear is faulty based on the ozone concentration, oxygen concentration and SF6 concentration.

2. A high-voltage switch cabinet environment monitoring method according to claim 1, characterized in that: Adjust the output voltage of the fan module. The specific algorithm is: Among them, u(k) is the output voltage of the fan module at time k, is the proportionality coefficient, For the integration phase, is the differential coefficient, e(k) is the humidity deviation at time k, e(k-1) is the humidity deviation at time k-1, and k is the sampling time.

3. A high-voltage switch cabinet environment monitoring method according to claim 1, characterized in that: The calculation formula for humidity deviation is: in, is the actual relative humidity collected at time k, is the expected value of relative humidity.

4. A high-voltage switch cabinet environment monitoring method according to claim 1, characterized in that: Determine whether there is a fault in the high-voltage switch cabinet based on the ozone concentration, oxygen concentration and SF6 concentration. If there is a fault, issue an early warning for the operating environment of the high-voltage switch cabinet; send the environmental parameters inside the high-voltage switch cabinet to the remote server for further judgment.

5. A high-voltage switch cabinet environmental monitoring system, characterized in that: It includes a data acquisition module, a humidity judgment module, a voltage regulation module and a fault judgment module; A data acquisition module is used to obtain the temperature, actual relative humidity, ozone concentration, oxygen concentration and SF6 concentration in the high-voltage switch cabinet; The humidity judgment module is used to compare the actual relative humidity with the expected relative humidity value. If the actual relative humidity is greater than the expected value, the voltage regulation module and the fan module are started; The relative humidity expected value is set based on the temperature obtained; A voltage regulating module, used for adjusting the output voltage of the fan module until the actual relative humidity is equal to the expected value; The fault judgment module is used to judge whether there is a fault in the high-voltage switch cabinet according to the ozone concentration, oxygen concentration and SF6 concentration.

6. The high-voltage switch cabinet environment monitoring system according to claim 5, characterized in that: It also includes a sensor assembly, a data acquisition module, a communication module, a host, and a wind model module installed in a high-voltage switch cabinet; The sensor components include temperature and humidity sensors, ozone sensors, oxygen sensors and SF6 sensors installed in the busbar room; temperature and humidity sensors installed in the trolley room, cable room and instrument room; The sensor component is connected to the data acquisition module, and the data acquisition module is connected to the host through the communication module; The host is provided with a data acquisition module, a humidity judgment module, a voltage regulation module and a fault judgment module.

7. A high-voltage switch cabinet environment monitoring system according to claim 5, characterized in that: The algorithm stored in the voltage regulation module is: Among them, u(k) is the output voltage of the fan module at time k, is the proportionality coefficient, For the integration phase, is the differential coefficient, e(k) is the humidity deviation at time k, e(k-1) is the humidity deviation at time k-1, and k is the sampling time.

8. A high-voltage switch cabinet environment monitoring system according to claim 5, characterized in that: The calculation formula for humidity deviation is: in, is the actual relative humidity collected at time k is the expected value of relative humidity.

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