Practice of SF electrical equipment in safe operation of power grid Dou Weidong (Dingxi Power Supply Company of Gansu Provincial Electric Power Company, Dingxi 743000, Gansu Province) has established relevant regulations and systems to discuss the maintenance and safe operation of SF gas and SF electrical equipment, and to discuss sf6 electrical The safe operation of the equipment provides the basis.
For the open-type substation, the a1 10 strong population awake the city -4) aluminum trifluoride weeping - æ ³bookmark1 1 Overview With the rapid development of power technology, "two networks" construction and renovation projects, the use of SF electrical equipment is rapid plus. This type of equipment meets the requirements of no oil, and meets the requirements of miniaturization and automation. Therefore, S6 electrical equipment has been widely used. Common SF electrical equipment includes: S6 circuit breaker, gis closed combination electric appliance, SF voltage transformer, S, current transformer, S6 insulated transformer, and various high voltage sleeves. Tube and so on. Although the insulation and arc extinguishing ability of sf electrical equipment is good, accidents may occur if improperly used, so we must pay great attention to the safety of S6 electrical equipment.
Advantages of SF gas and SF electrical equipment SF gas has high insulation strength and is advantageous for miniaturization of electrical equipment.
The SF gas has strong arc-extinguishing ability, and the SF circuit breaker contacts are slightly burnt and the maintenance period is long.
The medium recovery speed is extremely fast, the cooling characteristics are good, the fracture voltage of the S6 circuit breaker can be made very high, the performance of breaking the near-zone fault is particularly good, the use is safe and reliable, and the service life is long.
The SF circuit breaker has a large breaking capacity. When the small inductor current and the small capacitor current are disconnected, the arc extinguishing characteristics are good, and the operating overvoltage is not suitable.
The SF gas arc decomposition field does not contain substances such as carbon that affect the insulation ability, and there is no fire hazard. Therefore, such circuit breakers allow many times of breaking, simple installation operation, small operation and maintenance, and are safe and reliable.
The advantages of the SF combined electrical appliance (GS) spoon minimize the footprint and space of the entire power distribution unit, and the structure is very compact. The 110kVGIS footprint is only more important than the load center.
The fully enclosed electrical structure is immune to various natural environmental conditions such as pollution, rain, sand, dust and salt spray, reducing the possibility of equipment accidents, especially suitable for high-altitude areas with industrial pollution and harsh weather.
Installation is quick and easy, which can greatly shorten the installation schedule. Because GS has developed toward three-phase common, composite and intelligent, it is generally enclosed in a grounded metal body by a unit such as a clearing device, an isolating switch, a grounding switch, a transformer, a lightning arrester, a busbar, and a connecting member. composition.
SF electrical equipment operation and maintenance practice 41SF gas overview S6 gas has high insulation strength and good arc extinguishing performance, but it is generally installed in electrical equipment with high pressure (such as: 03MPa and 06MPa). Although SF gas is theoretically considered to be safe, non-toxic and non-combustible, due to S, the gas is colorless, odorless, and chemically stable. The density at 101325Pa20C is 6 16g LSF. The molecular weight is 14 605 amine. The atomic weight is about 5 times that of air. It is easy to deposit at the bottom of the space, and it is not easy to spread. If it is inhaled too much, it will cause dizziness, vomiting, etc., and in severe cases, it may die due to suffocation. At the same time, in the preparation process of S6 gas, it is possible to mix some toxic substances, and in the S6 electrical equipment, corona, spark and arc discharge will also produce a variety of toxic, corrosive gases and solid decomposition products. These gases are mainly fluorinated thionyl (SF), sulfurized sulfonyl (phantom F), sulfur tetrafluoride (SF), sulfur tetrafluoride (SF), sulfur dioxide (sn defluorinated disulfide (SF0) , monooxydefluorinated disulfide (SF0), etc.; solid decomposition products mainly include copper fluoride (cuf), difluorodimethylsilyl 42SF electrical equipment, leak detection and qualitative determination and quantitative measurement methods. Qualitative measurement Generally, the high-sensitivity probe is used to detect the leaky part of the device. The features are: sound and light alarm, convenient positioning. In the practice of the field, qualitative leak detection is more practical. The specifics include: simple qualitative leak detection method, pressure drop method, segmentation positioning and Partial accumulation method. The simple qualitative method is to use a general leak detector to detect the sealing surface of all equipment components and the extremely suspicious place of the pipeline connection. The method is simple to find the obvious local leakage. The pressure drop method is to use precise pressure. The meter measures the gas pressure, repeats the test every few days or tens of days, and combines the temperature conversion or the horizontal comparison to determine whether the air pressure drop occurs. The split positioning method is applicable to the three-phase SF gas path together with the electrical equipment. The SF gas system is divided into several parts and then leak-detected, which can reduce the blindness. The local accumulation method is to wrap the measurement part with a plastic cloth. After several hours, the leak detector is used to measure whether there is leakage of SF gas in the plastic cloth. The qualitative leak detection method is more commonly used at present.
In the operation practice, it is proved that the parts that are easily leaked by SF electrical equipment are: test ports, welds, aeration nozzles, flange joints, pressure gauge connecting pipes, sealing bases, etc.
Quantitative measurement has a bottle leak detection method and a partial dressing method, which should be carried out after inflating for 24 hours. The HEA2012 type leak detector or the LE2000 type leak detector can be used as a quantitative measuring instrument, which is safe and convenient, and is ideal. The criterion for quantitative measurement is that the annual air leakage rate is not more than 1%. In addition to the integrity of the operation monitoring equipment to ensure the gas pressure of the SF electrical equipment, the monitoring equipment such as SF pressure gauge and density meter are regularly inspected, and the SF electrical equipment is periodically leak tested. Test, find fault points in a timely and accurate manner, and develop treatment measures. Conditional oximeters can also be installed in the SF high pressure chamber, and alarm when the oxygen content is too low.
Generally speaking, the oxygen content should not be lower than 18%. 43 Measurement of micro water content The measurement of SF gas micro water content should be carried out after the humidity of the gas chamber is stabilized. The closed combination electric appliance should generally be carried out after inflation 241. It can be tested with P5 dew point micro water tester or DP9-S-type SF micro water tester.
Table 1. Table isf6 gas moisture content requirements (ppv / v) project circuit breaker arc chamber gas chamber other gas chamber handover acceptance overhaul after operation with different instruments to measure the same equipment, it is possible to get and use Gas piping is related to factors such as operation, so it is recommended to use the same instrument for measurement to ensure the comparability of test data.
Before measuring the SF gas in the SF electrical equipment air chamber, the air connection of the test instrument should be dried, otherwise the accuracy of the test data will be affected.
44SF electrical equipment safe operation At present, our company's 110kV and below substations are in "four remotes"
On the basis of more mature technology, the unattended operation mode is being vigorously promoted. Whether SF electrical equipment can operate safely and reliably is inseparable from the manufacturing quality, installation quality, operation inspection and maintenance and maintenance quality of the equipment. In the safety production practice, it is proved that the air pressure drop of SF electrical equipment is a common phenomenon, sometimes falling below the alarm pressure (such as: the GS of the Dingxi Power Supply Company's stability substation and the 1102 switching air pressure of the newly added substation). Some parts of SF electrical equipment may leak. The decrease of gas pressure will inevitably reduce the insulation strength and arc extinguishing ability of SF gas, which will bring serious hidden dangers to the safe operation of the equipment. Therefore, real-time accurate monitoring of SF electrical equipment pressure values ​​is very important. When the pressure is reduced or pressure is frequently pressed, the transmission of the signal should be timely and reliable. The abnormal data of the intelligent display should be notified to the running personnel and the maintenance personnel in time. The sf electrical equipment in operation should generally be tested for gas moisture content every three months. Because the moisture content of the gas increases with the increase of the outside air temperature, especially in the summer, the detection of the moisture content of the gas should be strengthened. If there are conditions, the on-line detection system of air pressure and moisture should be put into the SF electrical equipment.
5 staff training and protective equipment to improve the different data i may be related to the performance of the instrument itself, but also blishl breathe fresh air and wash hands, face, etc. with water: enkUetbookmark2 with the development of power technology, new products New technologies are constantly emerging and rapidly developing, especially sf electrical equipment. The equipment is miniaturized, composite and intelligent, and has high technology content. Therefore, we should educate the staff and must make each staff aware of sf gas. The basic characteristics, master the basic theoretical knowledge of sf electrical equipment and the safety requirements for working on sf electrical equipment, and master the relevant technical regulations, process standards and operating procedures, so that the staff can handle the maintenance and repair work, so that SF Electrical equipment plays a better role. In addition, staff should be strengthened to protect themselves and improve their protective ability (such as: when the outdoor sf electrical equipment leaks, close to the sf electrical equipment from the upwind, wear long-sleeved overalls when working, etc.) and pay attention to the release of staff protective equipment. If equipped with anti-virus respirator, special protective clothing (used when the equipment is dismantled and overhauled), use rubber gloves. There should be sufficient water source in the substation. After the workers contact the sf gas, the precautions for working on the 6SF electrical equipment should be difficult to avoid. The gas leakage of the SF electrical equipment is difficult to avoid, due to manufacturing quality, installation process, aging of sealing components, etc. Gas leakage and the infiltration of moisture are also common.
Gas leakage and moisture infiltration are the key factors that affect the long-term safe operation of S6 electrical equipment. Although S6 gas is theoretically considered to be safe, non-toxic, and non-flammable, excessive SF gas inhalation may cause dizziness, vomiting, etc., and may cause death due to suffocation. At the same time, in the preparation process of S6 gas, some toxic substances may be mixed in. During the switching operation, the arc generated will also act on S6 to produce toxic substances; therefore, it should be highly paid attention to during operation, maintenance and overhaul.
Proper preventive measures and medical ambulance measures should be taken before SF electrical equipment maintenance work.
When the S6 electrical equipment needs to be ventilated, the S6 new gas should be checked and accepted according to the new gas quality standard. The purity of the new S6 gas should not be less than 99.8%. The purity after charging into the equipment should not be less than 97% carbon tetrafluoride, air, moisture, Eight indicators such as purity and acidity should conform to national standards. All tubing must be flushed before inflating. After inflation, the air pressure is slightly higher than the required value to test the moisture content. The moisture content should be tested by a professional using a special instrument and prevent moisture from infiltrating during on-site inspection. When the equipment is filled with S6 gas, the relative humidity of the surrounding environment should be <80%. At the same time, the ventilation system must be turned on and the S6 gas should be prevented from leaking into the work area. The content of S6 gas in the air of the work area shall not exceed iL/L. When the staff enters the air chamber, the air chamber should be fully ventilated beforehand, and the air chamber can enter the air chamber when the oxygen content of the air chamber reaches 18% or more. Enter the SF power distribution unit room. If there is no SF gas content display at the entrance, you must first ventilate 15mn and measure the SF gas content with the leak detector. Try to avoid one person entering the power distribution unit for inspection, and no one is allowed to enter the maintenance work.
Before the SF electrical equipment is dismantled and inspected, the staff should be trained in special safety technical knowledge and the SF gas should be inspected. Take safety precautions based on the content of toxic gases. Maintenance personnel are required to wear protective clothing and wear a gas mask as needed. After opening the equipment cover, all personnel on the site should temporarily evacuate the site to remove the adsorbent and remove the dust. The maintenance personnel should be equipped with gas masks and protective gloves.
The gas in the equipment shall not be discharged into the atmosphere, and it shall be recovered by a purification device and used after being processed. Vacuum the device and rinse it with nitrogen for 3 times before disassembling the device.
The operator should stand on the windward side when recycling.
When the SF electrical equipment is reassembled, the sealing groove surface should be clean and free from scratches. The sealing ring is generally O-shaped. Seals (rings) specially prepared from high-quality materials such as neoprene, ethylene propylene rubber and fluororubber should be used. Used gaskets must not be used any more. Do not allow the grease to flow into the inside of the gasket (ring) to avoid contact with SF gas.
When SF electrical equipment is overhauled, the staff shall work in strict accordance with the work place, work scope, precautions, and dangerous points listed in the work ticket, three measures and the danger point analysis card. The maintenance process must be standardized. The duties of the staff, the rigor of the implementation rules and regulations, technical standards and technical standards should be specified and quantified so that they can be ruled and evidence-based.
7 SF electrical equipment management strengthens S, equipment management, SF electrical equipment maintenance, S6 electrical equipment inspection, S6 gas detection, test equipment, safety equipment, etc., should be set up by special personnel management, regular inspections, regular inspections, implementation at various levels Manager responsibility. The spare S6 gas should be stored in a spacious and well-ventilated environment, managed in the same way as the operating equipment, and a sound safety management system should be established. The staff should strictly implement this system.
8 Conclusions Over the years, the operation practice has proved that the use of sf electrical equipment in our substation has made a new breakthrough in safe operation. At the same time, the S6 related system formulated by Gansu Electric Power Company Dingxi Power Supply Company has been implemented, and implemented according to standards and systems. Therefore, many problems are found, and the problem is eliminated in the bud, which provides a strong basis for the elimination of hidden dangers of electrical equipment, thereby ensuring the safe and reliable operation of electrical equipment, and providing a strong guarantee for the safe production of the company.
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