In recent years, the Yanzhou Mining (Group) Company on the basis of research on the insecurity in the mine power supply system is running, the transformation of the original mine substation device, and create some new technologies effectively run effectively guaranteed the mine production safety.
1 Mine Flameproof mobile substation
Mine explosion-proof mobile substation developed by Yanzhou Mining (Group) Company in mechanical repair plant, the insulation level of mechanical strength of more than similar domestic products has reached the international advanced level.
Research group in the research and collection of relevant research data at home and abroad, the for domestic mining flameproof mobile substation existence imperfections, combined with the actual supply of fully mechanized coal face, identified low-loss, high-capacity mobile The goal of the substation, and work using computer simulation study, the combination of physical simulation and field tests. The new mobile substation with the new technology of epoxy resin cast oblong structure housing the body of the transformer and corrugated, moisture resistant, low temperature rise, less wear and tear, noise, flame resistant to moisture, safe and reliable operation, easy maintenance energy conservation. Practice shows: This achievement compared with the same capacity of ordinary mobile substation, an annual electricity savings of 10,000 kW · h, with a considerable energy saving effect, should be widely applied.
2 new flameproof dry-type transformer casing
Yanzhou Mining (Group) Company mechanical system repair plant in the analysis and comparison of a variety of domestic and foreign flameproof transformer strengths and weaknesses based on cooperation with the Coal Research Institute, Shanghai Branch, developed the most advanced new 1250kVA mine the flameproof KBSC series of dry-type transformers, shell oval corrugated exterior design reference to foreign products, in the case of no domestic production of professional manufacturers, the plant successfully developed their own research. The investigation of new, domestic this type flameproof enclosure, mechanical strength and thermal performance than similar products, adapted to today's explosion-proof transformer housing development requirements.
The flameproof enclosure has the following two advantages: ① mechanical properties. Flameproof enclosure oval corrugated structure, stress concentration area, the force is more evenly. Moreover, in a flameproof enclosure strength is relatively weak place additional ribs and strengthen angle on both sides of the flange, a sturdy walls of the box as a whole, to be strengthened so that the mechanical strength of the flameproof enclosure. ② thermal performance. The cooling area is an important symbol to measure the heat capacity of the transformer casing. The flameproof enclosure heat dissipation area of 22.5m2, 25% greater than the product of the same capacity. The top of the heat to the most concentrated semicircular corrugated board, the cooling area is increased by 2 to 3 times than the current widespread use of arc plates. In addition, the oval-shaped corrugated structure also accelerated the dissemination of heat to the surrounding housing. Forming and welding of corrugated board the entire housing manufacturing difficulties, they take a special process to prevent the destruction of local cracking, strain, twisting molding, design a specialized group of tooling, and in strict accordance with the welding parameters control group size to ensure the production quality of the housing.
China's first large-scale vacuum casting dry-type transformers and put into operation
Transformer Co., Ltd. Shandong Jin Manke manufacturing the first domestic 31500kVA vacuum casting dry-type transformers put into formal operation in Yanzhou Mining (Group) Company of Jining III coal mine, China marked the transformer manufacturing leapt to a new level.
Dry-type transformers have the advantage of flexible assembly, longer total box structure of the three-phase oil-immersed transformer winding, but the three-phase, respectively, manufacturing, final wiring group combination. The body of the drawing board fastening structure has the advantage of easy Install Remove. Windings with oxygen-free copper wound E-glass fiber strengthened thin insulating resin without fillers, vacuum impregnation casting and other advanced materials and processes. The high voltage winding series segment cylindrical structure and the axial heat airway, airway surrounding non shielding structure. The axial heat airway shield structure so that the airway voltage between both ends of the air gap is reduced to zero, to avoid the air as insulating medium bears transformer interlayer insulating interlayer insulating converted to the voltage between the airway shield domain winding conductor, the media insulator composed of a single resin and glass fibers, can withstand a voltage between the higher layer, to solve the technical problems for many years.
Lower dry-type transformers IP protection class shall be placed indoors have higher expectations than oil-immersed transformer and heat. Transformer heat dissipated in order to ensure sufficient number of cooling fans, need to be configured, and equipped with automatic temperature control system, cooling fan automatically starts when the transformer coil and air temperature gauge. Correctly reflects the transformer coil temperature thermal resistance temperature sensor on each phase are buried in the transformer coil. The mine's main transformer shall be provided with automatic voltage under load conditions and system voltage agencies. Traditional oil-immersed transformer selsyn a given signal OLTC technology behind the new transformer intelligent digital electric operating mechanism and the core component of the 16-bit MCU intelligent controller. The controller has the perfect interface, remote signal output BCD code and input, on-load tap changer remote monitoring and control, remote control, remote communication via RS-485 communication interface with the host computer communication. 110kV class transformer neutral point the thin insulation system, the need to prevent voltage generator. 110kV side the primary side of the three-phase, respectively, the "T" then three metal oxide surge arresters to prevent operating and lightning overvoltage.
4 epoxy cast dry-type transformers in the coal mine application
Epoxy cast dry-type transformers important industrial sector has replaced the oil transformers trend in the coal mine is still blank. Repair plant mechanical system of Yanzhou Mining (Group) Company and the Department of Materials developed KBSC-1250/6 mine flameproof epoxy cast dry-type transformers.
This mining flameproof epoxy cast dry-type transformers epoxy cast dry-type transformers for the body, together with the the oblong wholly corrugated flameproof enclosure. Flameproof Transformer body structure design based on electromagnetic design basis, from the perspective of loss reduction, enhanced dielectric strength, lower temperature rise, to adapt to the coal mine roadway transportation and parking, the dimensions of the transformer must be as much as possible small, especially the height direction to be reduced in size, so the flameproof transformer core of the body of the column diameter is too large, high, the diameter of the low voltage coil is also changed accordingly. The thermal stability of epoxy cast dry-type transformers of the key issues to be addressed in the coal mine applications.
They have taken the following measures: strict control epoxy material, select H-grade epoxy material ingredients to improve the thermal conductivity of the material in which to add the right amount of toughening agents, accelerators, curing agents and fillers, mechanical properties and insulation properties, its thermal expansion coefficient, and the winding copper consistent to avoid coil after casting thermal stress is generated due to a change in temperature, to prevent cracking of the winding, damage; coil using the high-temperature vacuum pressure once casting, sufficiently remove moisture improve the performance of the insulating properties and moisture resistance of the coil; core and between the high and low voltage coil and the coils are designed inside the airway, increasing the cooling area of the coil, to improve the cooling conditions; oblong full corrugated shell compartment burst transformer increases the cooling area of the outside world to the maximum cooling area increased by about 20% compared with the the domestic same capacity flameproof transformer enclosure at the top of the most concentrated heat dissipation area is more than twice that of traditional products, temperature l test and industrial test in the face of Jining Coal Mine 3301 proved to be superior cooling performance than similar products in the domestic transformer.
Distributed substation Computer Monitoring and Management System was born
Shandong University of Science and Technology and Yanzhou Mining (Group) Company Jining II coal mine for the health of the coal industry substation, developed a distributed station computer monitoring and management system for the safe production and scientific management has an important significance.
The distributed control system (DCS) is a computer-based technology, control technology, communication technology and graphics display technology (ie 4C technology), will be distributed through a communications network controllers (sub-station) in the industrial field, the inspection station, control and management The station engineers Station linked together to complete the decentralized control and centralized operation, management control system. A distributed computer network is the computer technology and communication technology in recent years, mutual penetration of a new technology developed rapidly, focused on contemporary computer hardware, software and communication technology development results, with good plasticity. The hardware structure is simple to operate and easy to use, easy to expand and repair, the user can, depending on the needs to select the system.
Jining II coal mine 110kV substation system is huge, double-loop power. Outdoor 110kV the double busbar contacted and dedicated bypass bus, 2-way 110kV outlet go Jining III coal mine, the 3 units 12500kVA main transformer assume all mine load. 110kV relay protection, has a line protection, parallel line protection, distance protection, busbar busbar differential protection of main transformer load, the composite voltage and current, and light and heavy gas, longitudinal differential, the direction of zero sequence relay. The 6kV fed qualifying Jun two-stage protection the 6kV room features 43 high counters, 6 Incoming Cabinet, 4 Contact cabinet, the arrester cabinet 32 to feed the outgoing cabinet, the use of small busbar, double busbar segment. The distributed substation computer monitoring and management system has the following functions: detection 110kV two circuit into the line, Jining III 2-way outlet and each of the main transformer current, voltage, active power, reactive power, active power, reactive power, peak-to-valley electricity and power factor; the 6kV room sub-disk current, voltage, power; analog-limit alarm and sequence of events recording; switching division indicate the nature of the accident trip indication mimic diagram.
6 110kV main transformer neutral point overvoltage protection configuration
Yanzhou Mining (Group) Company Jining III coal mine partial grounding system of 110kV main transformer neutral point gap zinc oxide surge arresters in parallel to the discharge gap and the gap voltage, overvoltage protection proposed new configuration principles: arrester focused on mine-voltage, operating voltage; discharge gap supplemented, main frequency overvoltage arrester rated voltage and over continued work.
The analysis showed that the single arresters and discharge gap to protect the main transformer neutral insulation is not desirable, how to take advantage of their respective long term and avoid short items with the direction to consider.
① follow the exchange gap metal oxide surge arresters using the guidelines "to ensure lightning impulse residual voltage to meet the requirements under the premise of 110kV graded insulation transformer may not be grounded, select neutral point gap zinc oxide surge arresters 1kA specifications rated The voltage is slightly larger than the transformer highest phase voltage, but common practice phase voltage is lower than the maximum phase voltage or rated.
② rods - rods discharge gap configuration principle is to compensate for the inability to perform the functions of zinc oxide surge arresters, close and more than more power frequency overvoltage arrester rated voltage duration in seconds, non-wholly coincide ferroresonance overvoltage. Rod - rod air gap distance break through the traditional 120mm restrictions, not only to ensure the discharge gap is not action line single-phase earth grounding system, and to ensure that the line single phase of the the 110kV terminal stations without power in the low-pressure side and lost ground point discharge gap does not only protect the main transformer neutral insulation and zinc oxide surge arresters to avoid unnecessary malfunction.
The ③ nearly millisecond duration exceed arrester rated voltage lightning surge and operation of wave, zinc oxide the arrester can easily discharge pressure limiting clearance action or not, the time before and after unimportant 500ms gap discharge current protection Tripping atmosphere overvoltage and operating voltage has long since disappeared. Parallel discharge gap in the arrester action before operation or simultaneous operation to reduce the steepness of the chopper is advantageous to increase the gap spacing also reduces the arrester after the operation of the residual pressure and the risk of a gap then operation will be reduced to the threat of a vertical insulating transformer small. (4) appear in the main transformer neutral point work more seconds more than the duration of the arrester rated voltage frequency over-voltage, non-ferroresonance overvoltage, zinc oxide surge arresters work frequency withstand voltage characteristics can not fully coincide bear, the bear can not protect the lives of the transformer neutral point heavy insulation, but the discharge gap can effectively limit this voltage. Discharge gap actions depend on the the gap current protection action in 0.5s transformer tripped circuit breaker, cutting off power to ensure that the explosion arrester will not avoid the destruction of the main transformer.
7 Transformer Gas protection malfunction analysis and preventive measures
Yanzhou Mining (Group) Company Dongtan coal mine main transformer tripping accidents were analyzed against the run, improper maintenance and other causes gas protection of the transformer malfunction caused the transformer tripping problem, take effective control measures.
Mine 35kV substation # 2 the main transformer SFFZ9-20000kVA type OLTC. The accident phenomenon as lights in the main control room emergency lighting 35kV substation, 2 # main transformer trip switch display sub-bit, no memory of the accident. Find the point of failure, and the cause of the malfunction and found that the accident record of the protection device, are obvious reasons for the trip, and therefore can only be based on setting # main transformer protection through a process of elimination to determine the cause of the accident, in order to identify the point of failure. 2 # main transformer appearance check that everything is normal, no obvious point of failure. Contact Electrical Laboratory # 2 main transformer electrical test project are normal, normal signal memory, so that the cause of the accident is not poor vertical action. Check # 2 main transformer protection device control circuit wiring and DL-221, identify the reasons for the X5, X6 board internal heavy gas protection device trip loop circuit burn out the shorted phenomenon, discolored four resistors surface color ring ; heavy gas the photocoupler signal circuit circuit blows, but intact, trip circuit protection trip test device no signal typical of secondary failure caused the malfunction.
The cause of the accident has three lines of human factors: the installation position signal to the oil temperature will be air-cooled disappear; transformer oil temperature setting (ie, high oil temperature) in the maintenance mistakenly transferred to 55 ° C; alarm signal communication board The damage did not discover. Therefore, the oil temperature exceeds the set temperature (air cooling start) value, the air-cooled device automatically run; body (high oil temperature signal is issued through relay protection device when the oil temperature exceeds a set upper limit temperature), and monitor the air-cooled operation; air-cooled non stop protection device body trip command and ontology trip signal sent through the relay. Precautions to avoid potential accidents caused by human factors in addition to strengthening the business training should be full and regular check transformer gas relay components of the two parts of the state intact, in strict accordance with procedures inspection; reliable and effective rain, moisture and anti-vibration measures thirds due to environmental reasons caused gas protect the malfunction; prevent the transformer running in dance touch probe.
8 transformer oil fault diagnosis regeneration treatment with anti-bad
Yanzhou Mining (Group) Co., Ltd. to carry out the fault diagnosis of transformer oil with anti-inferiority study with good protection, the protection of the transformer to support running play.
⑴ be analyzed to determine from the appearance. The outer shape of the oil analysis is the most basic method of diagnosis. Under normal circumstances, the transformer oil to brown or brown, acid value and water-soluble acid is often close to or exceed the value of GB Note, should attract attention or should not be reused; the oil cloudy whitish show that moisture in the oil; oil mere mention of dark description aging transformer oil; The oil blackened or glue smell transformer internal fault.
⑵ appearance with the gas chromatography and other methods comprehensive analysis and judgment. ① oil sample turbid white. If the gas chromatograph analysis showed that the H2 content exceeded the normal and little change in the content of other gases, can be substantially diagnosed as the transformer internal influent moisture analysis, combined with a breakdown voltage of the oil. Do micro-water analysis for further discrimination. Oil samples to produce a large number of H2 reason, moisture and iron a chemical reaction, the decomposition of water molecules in high electric field. ② oil sample the oil color black. Characteristics of oil gas H2 and C2H2 content of up to several thousand μL / L, transformer carbonized black. (3) binding analysis parameters to be judged. Do a good job in the laboratory analysis of transformer oil, water, acid value, water-soluble acid, breakdown voltage, dielectric loss factor and interfacial tension parameters. Moisture overrun Mifengbuyan allow moisture intrusion, the overtemperature run lead to aging of the solid insulation or deep oil deterioration, the need to replace the desiccant inside the respirator, lower operating temperature and vacuum filtration processing. Take reasonable and effective anti-inferiority measures to slow the aging of the oil. 1000kVA and above transformer at least to add antioxidants install a thermal siphon or anti inferior film sealing measures. The film transformer protection moistureproof role, filling desiccant main siphon moisture measures. Siphon silicone color from blue to red, indicating that the silica gel absorbs moisture to reach saturation must be removed, then dry. Insulating oil is not used or subject to different degrees of pollution and deterioration in use for some time, quality indicators over the quality of the oil can not allow standards to continue to use the oil-filled electrical equipment commonly used approach sedimentation method, mechanical filtration, centrifugation and vacuum filtration and so on.
9 110kV substation relay protection technological innovation
Yanzhou Mining (Group) Company of Jining II coal mine substation the original 110kV into the outlet and the main transformer relay protection system to be transformed into a state-of-the-art computer protection system, to adapt to the needs of a modern mine production.
Jining II is the company's first use of a the 110kV voltage substation powered mine, a total of two back into line, three rounds of qualifying, three SFLT-12500/110 main transformer, wiring is more complicated. The original protection question is: are complex electromagnetic components, wiring, components exposed contacts easily oxidized resulting in poor contact, greatly reduced the reliability and sensitivity. Difficult to maintain; protection setting tuning tedious low precision; disk area detection monitoring complex economy. The goal of this transformation is: try to simplify the wiring under the premise to ensure the safety of the power supply, and retain the original relay performance. In order to further improve the accuracy and reliability of relay protection, the need to increase the three sections of line overcurrent protection as backup protection, so that in the case of PT break in time; main transformer also increases the CT, PT disconnection protection. Therefore, they used four unified replace PXH-112X high-voltage line relay protection device DFP-210 microprocessor line protection device. Taken to change the operation mode of relay protection and improvement of the double-loop inlet and outlet, charged all the way to run all the way to power outages to transform. First transformation spare circuit test qualified investment in a run and then transform another loop.
Contrast before and after the transformation is as follows: the movement speed is generally slower becomes faster;; difficult to change the setting automatically becomes easier by the high sensitivity of selective and to prevent malfunction more difficult becomes easy access to a variety of characteristics. ; original input waveform anomalies response insensitive it is not easy to malfunction, now needs to analog and digital filtering handled properly may cause malfunction; able to achieve a reliable combination with other devices in the substation, will not affect the substation normal operation, to improve the running of the economy.
10 the mobile substation core failure analysis and repair technology
Yanzhou Mining (Group) Company Xinglong Coal Mine the 2005-3 # 2004-2006 15 # two KBSGZY-2000/6/3300 type mobile substation Masui use in the 3305 Face repaired, go to the B4318 face. ,2005-3 # two face the process of using mobile substation for 750kW rear the transports and 400kW loader supply 2004-2006 15 # mobile substation for of 1050kW front conveyor supply. Not obvious exception. Masui overhaul the B4318 face after to find core ground fault analysis and repair.
① be overhauled. 2004-15 # the mobile substation core shift, low-voltage winding by compressional deformation, low-voltage winding and the insulation layer between the core overheating, the the core taut device aging insulation overheating. Routine test, insulation resistance test by DC resistance tested and found to comply with the requirements, frequency withstand voltage did not pass the test. Found that the iron core iron yoke up and down part of the occurrence of inter-segment displacement, displacement core and clamps, the core relative clamps insulation missing, causing Core Grounding open the 2005-3 # the mobile substation core holder, the local iron loss increases, the temperature rises, the core tensioning device insulation aging. Overheating of the low voltage winding and the core insulating layer. Do the insulation resistance test, high and low voltage winding insulation resistance to 2500Ω; core insulation resistance to ground zero, he failed.
② reason analysis. Early product of the two mobile substation Yanzhou Mining (Group) Company Kikai repair plant, the core fixtures in the design defects the collision during transport or the core displacement under the influence of external force, causing the insulation pieces missing, leading to more point grounding, circulation formed between the ground point, so that the local iron loss increases, core fever, tensioning device and insulation plate heat aging core covering the paint off, while the coil insulation and causing serious damage, temperature protection device does not play The protective effect.
(3) repair program. Replacement of the deformation and damage to the insulation of the winding; replace the insulator core, Class H insulation material (clamps insulation and insulation board), redo the silicon steel sheet varnish displacement of silicon steel sheet occurs between segments 2005-3 # mobile substation core re-stacked; replace the tension with each increased by two and so taut with tension belt use rose tensioning better H200 polyester resin impregnated glass fiber banding tape; core and low-voltage winding between, between the high and low voltage windings with stays fixed Class H insulation materials, insulation boards; replacement silicone rubber sheet to deal with the insulation pad; replace corroded standard parts.
The harmonic transformer 11 and the DC component suppression technology research
Yanzhou Mining (Group) Co., Ltd., on the basis of the power system harmonic component and the DC component of the transformer harm study found its effective inhibition of the technical approach.
⑴ transformer harmonic component suppressed. Transformer due to the nonlinear characteristics of generated harmonics, transformer power system extremely broad, and so must pay attention to this harmonic pollution. For it is very necessary to improve the quality of power supply and ensure their safe and economic operation of the power system. Generally speaking, the suppression of the harmonic components of the transformer and eliminate harmonics following ways: (1) to consider from the transformer itself, can take advantage of the wiring of the transformer winding to suppress harmonics. Taking into account the same into a three-phase non-sinusoidal three times the phase of the harmonic component, it is usually to any one winding of the primary side or the secondary side of the three-phase transformer is connected into a triangle to provide a path to triple harmonic to inhibit the triple harmonics seriously affect the voltage waveform. (2) the use of transformer combination of passive filter for harmonic suppression. The traditional method is the passive filtering means installed in the high pressure side or low side of the transformer. ③ transformer combination of active filtering device for harmonic suppression. The basic principle of the active filter is detected from the object of compensation filter current generated by the compensation means and the one of the harmonic currents are equal in magnitude but opposite in polarity of the compensation current, so that the grid current containing only the fundamental component. Such means can change harmonic of the frequency and amplitude of the tracking compensation, and the compensation characteristic from the grid impedance. This inhibitory way dynamic of elimination and harmonic suppression and reactive power compensation.
(2) transformer DC component suppression. The DC biasing formation due to the transformer neutral point of the DC current transformer, the transformer magnetizing current sharp increase, caused by the excitation circuit overheating, noise and vibration increases. Current transformer slightly component suppression roughly the following methods: (1) transformer neutral point injection reverse DC current. ② in the series resistance of the neutral point of the transformer to reduce the flow through the neutral point of the DC component. ③ high voltage capacitor in series at the neutral point of the transformer-isolated DC component. This protection equipment abroad, the off-the-shelf devices, mainly suitable for small-capacity transformer to prevent the sunspot movement caused the larger DC current of the transformer overload burned. ④ change the DC current distribution measures. This method is the analysis of the distribution of the DC current in the grid, the main influencing factors and their sensitivity, and to take corresponding countermeasures.
Of 12 microcomputer protection in mine transformer
Compared to traditional mechanical relays, microprocessor-based protection because of its sensitive and reliable protection action, the ability to record failure information, remote control and management, and powerful self-test features, so that of all the mine power system of 35kV The substation has been rapid promotion. Yanzhou Mining (Group) Co., Ltd. is the use of computer protection products have NARI, Shandong Luneng, Zhe Jiang Sanchen on on several types. Commissioning, operation of the mine situation and problems of these products is summarized and analyzed.
Its main contents are as follows:
① operation and testing difficult. Some manufacturers of computer protection device front panel with full English interface, and the operation is more complex, higher requirements for on-site maintenance personnel. The manufacturer does not provide background analysis and debugging software, the lack of comprehensive testing means for site operators are familiar with and understand the operation of the microprocessor-based protection problems.
Standards ② products. Different products from different manufacturers using the data interface and hardware, using the respective standard software to calculate current and system parameters are also different standards. Different products, hardware and software is difficult to Universal, the grassroots protection needs to put more attention on device debugging and software analysis.
(3) control problems. At present, only a few coal mines use a centralized control system, most of the coal mines or using a stand-alone, resulting in a low degree of automation of the entire system; remote control of the microprocessor-based protection is turned off long-term, cause some of the functions of the computer protection device idle, can not meet the substation automation run requirements.
4 microcomputer protection function application is not enough. Some computer protection products used in the CPU is a 16-bit microcontroller, structure, clock and bus restrictions, limited functionality of its instruction address space, computing power is weak, and assembly language development platform is limited, can not give full play to the advantages of microcomputer products . The microprocessor-based protection to install and use, and most are still used in the inherent functions of the original electromagnetic relay or a slight increase. Microcomputer protection inherent in a wide range of protection and backup protection had not put waste microcomputer protection of resources.
Currently, they are looking for has been found that the problem solving measures for the early the mine mine transformer protection to a new level, really play the role of escort for safe production.
