Technical measures for the hottest electric anti a

Electrical anti accident technical measures

in order to successfully complete Mengzhuang thermal power project 2 × This measure is formulated to ensure the safe, stable and high-quality commissioning of 300MW units and prevent major electrical accidents

2.1 compilation of anti accident technical measures (compiled by the Department of safety supervision and production coordination of the Ministry of electric power)

2.2 measures for safety evaluation of parallel operation of power plants (issued and tried out by the national power safety commission in 2000)

2.3 code for investigation of electric power production accidents (1992)

2.4 Mengzhuang thermal power project 2 × Design and equipment technical documents of 300MW unit

3.1.1 for important circuits such as DC oil pump, fire water pump and battery DC power line, it should meet the national standard gb12666 Class a fire-resistant cable under fire resistance test conditions

3.1.2 in terms of design, the design sample drawing of cable fire blocking should be given, and the interlayer fire-resistant partition should be set between the control cable and the power cable. Fire detection and alarm devices with reliable performance that adapt to the site environmental conditions shall be installed at the specified positions

3.1.3 the fire pump room shall have standby power to ensure that the water pump starts to supply water within 5 minutes

3.1.4 consider the protection cooperation of 380/220v low-voltage auxiliary system as a whole, and the power line should be properly equipped with secondary protection to facilitate the cooperation between upper and lower levels

3.1.5 in terms of construction, the construction shall be carried out in strict accordance with the design drawings and construction specifications, the special construction organization design of cables shall be prepared, and the cable laying, the construction of fire prevention facilities and the production of cable heads shall be accepted in accordance with the specifications

3.1.6 pay attention to the operation management of 6kV and 380V high and low voltage power cables, conduct regular patrol inspection, and ensure that the fire prevention facilities of cable interlayer are complete and strictly implement the work ticket system

3.1.7 the operation duty room should be equipped with a certain number of respiratory protective devices with compressed air in case of emergency

3.1.8 the smoke exhaust fans in the distribution room, control room, relay room and electronic room are reliable and normal

3.2

measures to prevent electrical casualties

3.2.1 after the high voltage withstand voltage test wiring of generator, transformer, bus, etc. is completed, the person in charge of the test should re check the correctness of the wiring and confirm that the safety officer should be on site

3.2.2 the work and operation on live equipment shall strictly implement the "two tickets and three systems"

3.2.3 site staff must pass the safety regulations examination

3.2.4 work on live secondary current and voltage circuits should be supervised by special personnel to prevent open circuit and short circuit

3.2.5 the shell of high-voltage test equipment must be grounded. The grounding wire should use multi strand soft copper wire with a cross-section of not less than 4mm2, and the grounding should be reliable

3.2.6 the power supply for the test shall have a double pole switch with obvious open circuit and a power indicator. When the wiring is changed or the test is completed, the test power supply shall be disconnected first, the equipment with capacitance shall be discharged, and the high-voltage part of the booster equipment shall be short circuited and grounded

3.2.7 when conducting the power on test on the secondary circuit of the voltage transformer, the primary circuit must be disconnected from the voltage transformer to prevent high voltage from hurting people at the primary side, and it is strictly prohibited to short circuit the secondary side of the voltage transformer

3.2.8 when conducting the switch remote transmission test, a special person should be assigned to monitor the switch, and there should be local stopping measures. There should be communication between the remote and local

3.2.9 electrical testers should strictly implement the corresponding chapters in the safety work regulations for electric power construction

3.2.10 when working on site, pay attention to the surrounding environmental conditions to avoid being injured by others

measures to prevent electrical misoperation accidents

3.3.1 the anti misoperation system and the main equipment are put into operation at the same time

3.3.2 strictly implement the "two votes, three systems"

3.3.3 operators must pass the pre job training

3.3.4 for important test operations, the project leader should also monitor them in addition to operation monitoring

3.3.5 for the confirmation of the electrical equipment to be operated, it should be confirmed by both the operator and the guardian to strictly prevent the wrong interval from misoperating the equipment. It can be seen from the formula

3.3.6 before the electrical equipment is put into operation, the operator should check and confirm that the name and mark of the equipment are clear, firm and correct, and have passed the acceptance of relevant units

measures to prevent generator damage accident

3.4.1 increase the hand wrapped insulation test at the end of generator stator winding

3.4.2 add partial discharge test of generator stator winding

3.4.3 strengthen the monitoring of stator winding, iron core, inlet and outlet air temperature

3.4.4 during the test run, if the stator grounding signal cannot be determined as a false signal, the machine shall be shut down immediately for inspection

measures to prevent large transformer damage and transformer explosion

3.5.1 add partial discharge test items to start-up transformer and main transformer

3.5.2 when receiving power for the first time, adjust the tap positions of the on load voltage regulating tap changer to verify its correctness

3.5.3 avoid trial operation of transformer without any test and inspection after experiencing outlet short circuit

3.5.4 prevent moisture and air from entering the transformer: the desiccant should be kept dry, and special attention should be paid to removing the internal air before putting into operation. For example, the residual gas should be removed many times at the casing riser, the dead zone in the oil pipeline, the top of the cooler, etc., and all submersible pumps should be started to circulate the oil to make the residual gas escape

3.5.5 prevent welding slag, copper wire and other sundries from entering the transformer: the transformer should be covered or inspected during installation, and the sundries at the bottom of the box should be completely removed. The oil pipeline, cooler, submersible pump and oil purifier should be completely removed and installed correctly before installation

3.5.6 prevention of transformer insulation injury: the insulation injury of the transformer should be prevented during lifting inspection. When installing the transformer bushing, attention should be paid not to kink the lead wire, and do not lift and pull the lead wire too hard to damage the insulation of the lead root and winding. The bolts and pressure nails of the clamp and the bolts of each insulation support should be tightened to prevent deformation and damage when being impacted by current during operation

3.5.7 prevent the winding temperature from being too high, insulation deterioration or burnout: when the cooler of the transformer fails, the allowable load and time shall operate according to the manufacturer's regulations. The cooling system with strong oil circulation must have two reliable power supplies and can be switched automatically, and the signals are complete and reliable

3.5.8 prevention of breakdown accident under working voltage: when 220kV and above transformers are put into operation, it is not suitable to start multiple coolers, but should be started one by one, so as to avoid oil flow zone, which not only makes the equipment have a fair and simple operation mode, but also makes the transformer oil chromatogram abnormal in operation. If there is discharge fault, partial discharge test should be carried out for further judgment

3.5.9 prevent the misoperation and refusal of the protection device: the gas protection should be installed and adjusted correctly, the protection power supply should be reliable, and corresponding measures should be taken when a certain protection is out of service. In case of short circuit at the outlet or near area of the transformer, ensure that the switch trips correctly to prevent the transformer from being damaged by a long short circuit time. In case of transformer with short circuit at outlet and near area or transportation collision, the winding state shall be tested and checked according to the specific situation. If possible, the winding deformation measurement can be carried out to identify whether the components in the transformer are deformed and damaged

3.5.10 prevention of multi-point grounding and short-circuit fault of iron core: the insulation of iron core should be tested during lifting inspection. If there is multi-point grounding, it should be checked and eliminated. Pay attention to check the gap between the top of middle cover and the clamp on the iron core and the insulation of core bolts should be good

3.5.11 prevention of casing flashover and explosion accidents: the casing should be kept clean to prevent pollution flashover and flashover in heavy rain. Pay attention to the changing trend of dielectric loss, capacitance and chromatographic analysis results of oil paper capacitive bushing. During operation, pay attention to check the heating condition of the outgoing line terminal and regularly use infrared detection

3.5.12 lead accident prevention: during installation, pay attention to check whether the lead, grading ring, wood bracket, bakelite screw and other parts are deformed and loose during operation, and remove the burrs and sharp corners on the exposed lead to prevent discharge breakdown during operation

3.5.13 prevention of tap changer accidents: before the transformer is put into operation, confirm that the contact resistance of each tap changer is qualified, and pay special attention to the correctness of the indicated position of the operating mechanism

3.5.14 the sampling period of the chromatographic test of dissolved gas in the oil of the new transformer should be implemented according to the ministerial regulations, which should be included in the chromatographic monitoring range from the actual electrification, and the sampling and detection time interval should be determined according to the actual situation, and the oil samples should be analyzed in time

3.5.15 prevention of transformer fire accident: special attention should be paid to the quality inspection and operation monitoring of bushing to prevent explosion and oil injection during operation. The fire prevention facilities of transformer shall be perfect

3.5.16 the newly installed domestic transformer should be analyzed for dissolved gas in oil and measured for trace water in oil before being put into operation. The current transformer of electronic experimental machine shall measure the Tg of main insulation and end screen to ground δ And capacitance, and partial discharge measurement if necessary. The Tg of the electromagnetic voltage transformer body and insulation support shall be measured δ， If necessary, partial discharge measurement shall be carried out for 220kV and above capacitive voltage transformers. At the same time, the insulation resistance of secondary windings and DC banks shall be measured, and the test results shall be compared with the factory value and standard value. If there is a big difference, the reasons shall be analyzed, and unqualified transformers shall not be put into operation

3.5.17 after the installation test of the transformer, before putting into operation, pay attention to check whether the capacitor end screen and base of the current transformer are grounded, whether the X (or N, b) end of the high-voltage winding of the voltage transformer and the base are grounded firmly and reliably, and should be directly and obviously grounded. The transformer frame should have a reliable connection with the grounding

3.5.18 the primary lead of current transformer shall be in good contact, and the secondary lead out terminal shall be provided with anti rotation measures to prevent the internal lead from being twisted

3.5.19 in order to prevent the series resonance overvoltage from burning the voltage transformer, during the system wear test to 30million cycle operation mode and switching operation, it should be avoided to use the circuit breaker with fracture capacitance to switch the empty bus of the charged magnetic voltage transformer. If the operation mode cannot meet the requirements, other preventive measures should be taken

3.5.20 in order to avoid expanding the impact range of the accident in the case of the breakdown accident at the bottom of the capacitor core of the current transformer, attention should be paid to the correct installation direction of the primary terminals L1 and L2 and the polarity connection mode of the secondary winding, so as to ensure the normal operation of the bus differential protection