The subway power distribution system in a large number of application of nonlinear load, mainly divided into two categories:
●Higher harmonic produced by the traction rectifier inverter device (5, 7, 11, 13, 23 times and 25 times - nearly a century, inferior)
●A large amount of non-linear load of transformer substation, the subway station (produces three, five, seven - hundreds of strange inferior harmonic) such as switching power supply, UPS power supply, computer, guiding equipment, switches, communication signal equipment, AFC/BAS, FAS of equipment, frequency conversion governor, VVVF elevator control, fan, water chiller, modern energy-saving lighting (LED, etc.) and so on.
Shanghai shentong metro
group co., LTD. Metro line 5
●Capacitance compensation ark overheating damage of a site Destroyed, for security reasons, the whole line capacitance Compensation ark is to stop using, power factor 0.6 ~0.7; The orange Hao the electrical test, power distribution system System contains a lot of harmonic, harmonic current on the high side,
The current distortion is larger.
●Two low voltage side of transformer in distribution system's installation 1 orange, Hao the electrical CHHPA - 300 a / 400 v - 4 l harmonic purification plant, the power factor > 0.98, harmonic content < 5%; As of Now safe and reliable operation. Harmonic purification configuration in total:
●CHHPA type harmonic purification plant (300 a) : 2 sets of configuration location: transformer room.
●CHHPA - B type harmonic purification devices: 20 units, configuration location: station guidance system, internal communication, external communication system, the public security communication system, signal system, AFC automatic ticketing system, BAS, FAS system, escalators, lifts, etc.
After using Sahs system governance waveform is as follows:
Shanghai shentong metro group co., LTD. Rail transit line no.5 Sahs system management, revenue is as follows:
Shanghai metro line 5, 11 station 1100 kw active load, all electricity for the whole year is about: 70 million yuan currency, after Sahs system governing the economic benefits of the assessment is as follows:
●Only transformer to reduce the capacity of a design, each 33 kV / 0.4 kV according to specifications than 1600 kva transformer of 1250 kva transformer price to save 25000 yuan RMB, the whole line of one-time investment to save 1 million yuan.
●Refer to 0.9 from 0.8 0.4 kV system power factor, reactive power loss decreased by 12%, reduced to 220/110 kV transformer, the whole line power loss decreased by 2%, the annual average electricity saving about $1.36 million.
●0.4 kV increased from 0.8 to 0.8, the system power factor and harmonic interference purification, to comprehensively consider the factors of reducing a transformer capacity, active output the merchants in the station that electricity capacity can be increased by 5%, electricity income increased by 5%. The whole line increase their income is about 3.5 million yuan.
●Reduce equipment maintenance costs, reduce equipment wear and tear, reduce equipment investment, etc. Harmonic after purification, to avoid heat loss in the transformer, cable has resulted in the accelerated ageing of the equipment, prolong the service life of equipment, thereby reducing the costs of maintenance, repair, replacement of spare parts, more obvious economic benefit.
Can be seen from the above analysis, through the power quality management, can purify the power distribution system harmonic interference, to reduce the loss of the system and make the safe and efficient operation of distribution system, especially for high electricity safety requirements of the subway stations meaning is greater. Power quality management not only in the lines of transformation has made great economic benefits, in new subway lines to the harmonic purification design concept, can also optimizes the allocation of system capacity, and save a lot of initial construction investment.