电气讲义(改).doc

Table of ContentsChapter I Introduction31 Introduction to WASSIT power plant electrical system32 Overview of electrical system33 Operation Mode for 400kv and 132kv Systems54 Operation mode for 6kv station service system65 Operation mode for 400v plant service system86 The whole plant DC power system127 Uninterruptible power supply system15Chapter II electric generator181 Maintenance for operation and monitoring of generator in normal operation182 Operation mode of voltage, frequency and power rate change29Chapter III transformer311 Work before putting into operation of the transformer312 Putting into operation and switching off of the transformer333 Operational maintenance of the transformer354 Transformer operation regulations385 Cooling system of the dry-type transformer42Chapter IV direct current system441 Monitoring of the charger442 Inspection of storage battery453 The inspection and patrol of DC distribution panel46Chapter V UPS481 Indication and operation unit of UPS device482 UPS operation mode523 Inspection during UPS system operation61Chapter VI power distribution unit621 The general requirements of power distribution unit622 Busbar and switch blade643 Switch66Chapter I Introduction1 Introduction to WASSIT power plant electrical system1.1 Centralized control includes generator-transformer unit, high voltage transformer, start-up standby transformer and every station service transformer, bus system with 6KV and 400V voltage grades, system with 220V direct current and UPS system. 1.2 Network control includes 400KV and 132KV system, system with 110V direct current and UPS system. 2 Overview of electrical system 2.1 Main wiring of 1400kV system is 3/2 wiring mode. 400kV system switch adopts LW25-420/Y4000-50 high-voltage AC ceramic column SF6 circuit breaker produced by Xian Xidian High Voltage Apparatus Co., Ltd. Monitoring and control operation for 400kV system equipment is realized by computer monitor system NCS. 2.2 132KV main wiring mode is sectionalized double-bus configuration. 132kV system switch adopts LW25A-145 high-voltage AC ceramic column SF6 circuit breaker produced by Xian Xidian High Voltage Apparatus Co., Ltd. Monitoring and control operation for 132kV system equipment is realized by computer monitor system NCS.2.3 The first series and second series of 400KV system are connected with 132KV A/B bus by two interconnecting transformers (three-phase oil-immersed forced air cooled auto-transformer with on-load tap changer, the capacity is 250/250) respectively.2.4 One main transformer is set in each unit (three-phase oil-immersed forced air cooled transformer with no-load tap changer, the capacity is 400MVA), one high voltage transformer (three-phase oil-immersed air cooled transformer with no-load tap changer, the capacity is 31.5/20-20), and one start-up standby transformer (three-phase oil-immersed air cooled transformer with on-load tap changer, the capacity is 50/31.5-31.5) is set for every two units. The power supply is introduced from 132kV power distribution unit for public load power supply of all plant as well as for load power supply for unit start and stop and spare power supply for high voltage transformer of unit.2.5 Separated-phase enclosed bus is used for connection between generator outlet and main transformer, high voltage transformer, exciting transformer, (separated-phase enclosed bus adopts micro-positive pressure air charging device: air pressure in bus shell is 500-2500Pa) and two sections of 6kV bus is set in each unit ( 6KV A and B respectively). Power for peripheral equipment and 6kV utility system is supplied by two sections of 6kV public bus (6kV public section A and 6kV public section B), each section bus is spare for each other, and the power is supplied from start-up standby transformer 1 and start-up standby transformer 2. The main load includes hydraulic transformer, chemical water transformer, public transformer, power of water taking pump vessel, transformer for front area of plant and fire pump power. The switchgear is middle mounted metal armoured switchgear produced by Shanghai Guangdian Electric (Group) Co., Ltd and the switchgear adopts vacuum circuit breaker and high voltage fuse plus vacuum contactor with spring operating organization. 2.6 Low voltage transformer is allocated in pairs and for spare each other; the two low voltage bus sections are corresponding to the same bus sections of 6kV high voltage bus respectively. Low-voltage AC system (including security power supply), low-voltage AC system of main power house adopts neutral-point solid ground system. Power supply mode for low-voltage plant motor: two levels of power supply including power center (PC) and motor control center (MCC). Generally, 75200kW motor is supplied by 380V PC and motor under 75kW is supplied by MCC (except for security load). 380V PC/MCC switchgears adopt MS low-voltage whole set switchgears produced by Changshu General Electric Factory Co., Ltd. 2.7 DC control voltage includes 220V and 110V, which comes from DC accumulator system. Normal operating voltage of 220V DC system is 230V and variation range is 225-235V. Normal operating voltage of 110V DC system is 116V and variation range is 113-118V. Rated voltage for motor of DC oil pump is 220V DC and is connected with DC accumulator system. 3 Operation Mode for 400kv and 132kv Systems 3.1 Normal operation mode for 400kV3.1.1 56MVA bus reactor is set inside 400kV system and laid on 400kV bus. When the system voltage reaches 405KV, turn off 4061 switch and use reactor. 3.1.2 When 400kV system is normal, operate bus I and bus and there are 5 complete series. In the first series, corresponding equipment for switchers 4011, 4012 and 4013 is interconnecting transformer 1 and main transformer 1, in the second series, corresponding equipment for switchers 4021, 4022 and 4023 is 400KV line 1 and interconnecting transformer 2, in the third series, corresponding equipment for switchers 4031, 4032 and 4033 is main transformer 2 and 400KV line 2, in the fourth series, corresponding equipment for switchers 4041, 4042 and 4043 is 400KV line 3 and main transformer 3, in the fifth series, corresponding equipment for switchers 4051, 4052 and 4053 is main transformer 4 and 400KV line 4. Switches on both sides of generator-transformer unit are controlled by corresponding unit DCS, other 400kV switches are controlled by NCS system. Note: 400KV switch, rated current of knife switch is 4000A, rated current of 400KV line cable is 1200A and outgoing line load is controlled according to current. 3.2 Normal operation mode for 400kV3.2.1 132kV system in normal state is operated in four sections of bus, namely 132KV bus IA, 132KV bus II A, 132KV bus IB and 132KV bus B respectively, which are connected by section A buscouple and section B buscouple switches. Bus IB and bus IA, bus A and bus B are connected by subsection I and subsection switches respectively. 3.2.2 Eight 132KV output lines are distributed in 132KV bus IA and 132KV bus A, the normal operation mode is that knife switch for odd number line bus is in bus A, and knife switch for even number line bus is in bus A. There is no special reason for this condition but it is easy to remember. Side switch for 132KV line in this plant has no synchronizing device, in the normal condition, firstly close 132KV line switch of this plant and then connect the side switch to be simultaneously closed. 3.3 Rest equipment for 400KV and 132KV systems3.3.1 Switches 4011 and 4012 in the first series of 400KV system are connected with 132KV section A bus through interconnecting transformer 1, switches 4022 and 4023 in the second series of 400KV system are connected with 132KV section B bus through interconnecting transformer 2 and interconnecting transformer on-load tap changer can be operated on NCS. 3.3.2 Start-up standby transformers 1 and 2 are distributed in 132KV section A bus and 132KV section B bus respectively as spare power supply of four units station service and 6KV public sections A/b power supply. 4 Operation mode for 6kv station service system 4.1 Operation mode for 6kV station service system:4.1.1 Two lines of station service bus are set in every unit respectively. Take unit 1 as example, the lines are 6KV section A of unit 1 and 6KV section B of unit 1. When each unit operates in normal condition, station service power is supplied by high voltage transformer through main transformer, spare power switch for 6kV station service bus is hot spare and interlocking of station service is operated normally; when generator-transformer unit stops, station service power is supplied by start-up standby transformer 1 or start-up standby transformer 2. 4.1.2 During normal switchover for 6kV station service bus, non drop-outs switchover shall be realized by parallel switchover through fast switching. Whether supply power when station service power switches to start-up standby transformer or supply power when start-up standby transformer switches to station service power, the station service bus can be operated without interruption.4.1.3 Start-up standby transformer is three-winding transformer, group A low voltage side of start-up standby transformer 1 is supplied for public section A and spare for 6KV section A of unit 1 and 6KV section A of unit 2; group B low voltage side is spare for 6KV section B of unit 1 and 6KV section B of unit 2. Group A low voltage side of start-up standby transformer 2 is spare for 6KV section A of unit 3 and 6KV section A of unit 4; group B low voltage side is supplied for 6KV public section B and is spare for 6KV section B of unit 3 and 6KV section B of unit 4. 4.1.4 6KV public section A bus and 6KV public section B bus are spare for each other. In the normal operating conditions, switch for two sections of buses incoming lines is operated, interconnection switch between buses are in hot spare state, and interlock is input automatically. When some incoming line switch is off, the interconnection switch will be close automatically. Equipment on bus can keep the original operating state. Similarly, break interconnection switch, and power supply for itself will be made automatically. 4.1.5 When faults of main transformer and high voltage transformer and so on cause whole units stop, spare power supply for station service ensures continuous power supply during unit working with slow switching method through automatic device. The main transformer or high voltage transformer protects starter switch of exit action, firstly trip off work incoming line switch, after confirming the working power supply is tripped off, automatically close spare power switch. 4.2 Notes During switchover of station service power, there may be unsuccessful switchover which is normally caused by higher deviation between low voltage side voltage of start-up standby transformer and exit voltage of generator. Adjust generator idle work as much as possible, control exit voltage to make paralleling voltage on both sides approach, ordinarily, we dont recommend to adjust start-up standby transformer on-load tap changer to adjust voltage. Skewing of phase angular difference also can cause this condition and similar condition has occurred which is adjusted by relay protector. 5 Operation mode for 400v plant service system 5.1 400V low voltage station service system (PC)5.1.1 Two operating transformers are set in every unit with dark spare method and 6KV working section A and B are used for power supply respectively. Double sets of auxiliary engines and MCC in pairs are connected in section PCA and section PCB respectively; as well as providing thermal control power of unit and cooler power of main transformer. 5.1.2 Two power cooling tower transformer are set in every unit with dark spare method and 6KV working section A and B are used for power supply of power cooling tower load of this unit. 5.1.3 Lighting transformer is set in every unit and 6KV working section B is used for power supply and lighting transformers every two units are spare for each other. Unit 1 and unit 2 are spare for each other and unit 3 and unit 4 are spare for each other.5.1.4 One fuel oil transformer is set in every unit and 6KV working section A is used for power supply and fuel oil transformers every two units are spare for each other. Unit 1 and unit 2 are spare for each other and unit 3 and unit 4 are spare for each other.5.1.5 Two low-voltage public transformers are set every two units with dark spare method and 6KV public section A and B are used for power supply of cooling and onload voltage regulation for start-up standby transformer and public load of main power house, such as load of air-conditioning & ventilation and dosing sampling and so on. 5.1.6 Two hydraulic transformers are set every four units with dark spare method and 6KV public section A and B are used for power supply of air compressor room and public load power of relevant water treatment outside main power house (including power for start-up boiler and gas regulator station. 5.1.7 Two chemical water transformers are set every four units with dark spare method and 6KV public section A and B are used for power supply for public load of relevant chemical treatment outside main power house. 5.1.8 One 400V transformer for front area of plant is set in stage I and 6KV public section B is used for power supply for power supply of plant building.5.2 400V low voltage station service system (main MCC power supply)5.2.1 MCC bus in the section of security MCCA & B is set in each unit, each MCC bus in the section of security MCCA & B has 3 ways power supply, and they are 400V working PC A/B section and diesel generators. It is the vital power supply of the main power supply unit. 5.2.2 Bus of steam engine MCCA&B& section is set for each unit, the power of steam engine MCCA&B& section is supplied by 2 ways power supply, they are 400V working PC A/B section. It mainly supply power for side auxiliary generators, electric generator and plant hyper variable cooling power supplies.5.2.3 Bus of boiler MCCA&B MCC is set for each unit and they are supplied by 400V working PC A/B section. It is mainly supply power for boiler side auxiliary generators.5.2.4 Bus of overhaul MCC bus is set for each unit and supplied by #1&2 engine 400V public PCA&B section or #3&4 engine 400Vpublic PCA&B section. It is mainly for each unit overhaul and overhaul of power supply box.5.2.5 Bus of air pressure engine room MCC A&B section is set for four units. The units have no backup and respectively supplied by the 400V hydraulic power A/B section. It is mainly supply for the air pressure engine room thermal control power supply and the dryer power supply of the whole plant.5.2.6 Bus of circulating water pump house MCCA&B section is set for each two units. The units have hidden auxiliary mode and respectively supplied by the powered tower PC B section of each unit. It is mainly supply for the recycle pump room power supply and thermal control power supply.5.2.7 Bus of fuel oil MCC A&B section is set for four units without backup, and the fuel oil MCC A&B section has 2 ways of switch power supply and supplied by 400V fuel oil PC& section. Fuel oil MCC B section has 2 ways of switch power supply and supplied by 400V fuel oil PC& section. It is mainly supply for storage battery charging of the oil region and the auxiliary motor.5.2.8 Bus of water pump vessel MCCA&B section is set for each two units. The units have hidden auxiliary mode and respectively supplied by 6kVpublic A/B section. It is mainly supply for 5 water pump and power supply of accessory equipments.5.2.9 Bus of net control building MCCA&B section is set for four units, the units have hidden auxiliary mode and respectively supplied by #1&2 engine 400V public PCA section and #3&4 engine 400V public PCA section power supply. It is mainly supply for all kinds of device power supply and communication power supply of the booster station system.5.3 Arrangement situation of 400V voltage sourceThe 400V working section of the units is arranged at the 0 m layer of the engine room, lighting section, heating and ventilation section, batteries, diesel generators arranged on the 0 m layer of the control building, 400V public section, 400V security section, DC screen, UPS screen, protection cabinet of the generator-transformer unit, fast cutting device screen, server failures recorded wave screen are arranged in the electrical room of 6.3 m layer.MCC are generally arranged in accordance with the principles that the arrangement is closing to the supplied load.Operation mode of emergency power supplyA set of fast start diesel generator is set for each unit as the emergency power supply of the unit. Two sections of 400V security MCC bus are set for each unit and separately supplied by the 400V working section PCA or B power supply of the plant when it is in normal operation, and its power is supplied by the fast start diesel generator in emergency.5.4 Operation mode of the bus of 400V security section (take the example of 2# engine 400V security MCCA section)5.4.1 The security MCC of each unit consists of two buses, and each MCC bus has 3 ways of power supply. The bus of the 3 ways power supply of the 2# engine 400 V security MCCA are 400V working PCA section, 400V working PCB section, the 1st diesel engine. Normal operation situation: 400V working PCA section power switch (QF1) closing, 400V security transformation MCCA incoming breaker (QF3) closing, 400V working PCB section power switch (QF2) closing, transformation MCCA incoming breaker (QF4) hot spare, the 1st f diesel engine diesel engine (QF5) hot spare, MCCA segment automatic switching device inputs. When breaker QF3 opens, QF4 will