pt gmt32 (b) special measurement circuit of small circuit breakers-ag凯发k8国际
uses and features:improve the energy metering accuracy,reduce the comprehensive error of electric energy metering device,has been the important goals of electricity management departments。owing to the comprehensive error of electric energy metering device is current、the voltage transformer composite error、watt-hour meter and voltage circuit voltage drop caused by the errors,although the current with high precision、the voltage transformer and electricity meter,make the electric energy metering accuracy is greatly improved,but more problems due to the measurement circuit,thus the accuracy of electric energy metering device also cannot achieve a satisfactory effect。
voltage circuit including secondary cable pressure drop of the voltage drop,export voltage transformer circuit breakers(or fuse)the pressure drop and relay、the pressure drop of terminal blocks, etc,in order to reduce the pressure drop of the voltage loop,at present has taken many effective measures,such as increase the cable conductor cross section,shorten the length of cable(if use electricity meter to devolve billing,decorate in the configuration area),billing use special transformer,reduce the voltage loop of the intermediate links, and so on are the voltage circuit had a significantly lower voltage drop。but export voltage transformer circuit breaker(or fuse)the pressure drop of the problem is still not solved completely,thus to some extent, has become a limiting thetime "element measurement precision is improved。
because at present, for some ⅰ、 ⅱ kind of electricity load,required voltage loop un secondary voltage drop of 0.5 ~ 0.25%,which includes cable、switch electrical appliances and terminals, such as total pressure drop allows only 0.5 v ~ 0.25 v,excluding certain pressure drop cable and terminal,the pressure drop for switching element itself has been minimal。and now is widely used in electric power system voltage transformer secondary circuit breaker or fuse,its pressure drop are larger。under normal circumstances,ordinary breaker or fuse,the rated current 1 a 0.67 ω internal impedance;current is 3 a 0.25 ω internal impedance;current is 5 a 0.08 ω internal impedance,so much resistance,its pressure drop exceeds allowed pressure drop,so that the power supply division。
in addition,export voltage transformer circuit breakers(or fuse)there are other performance requirements,such as the instantaneous tripping current should be small enough,time should be enough to move fast,and can well protect circuit switch equipment。commonly used general circuit breaker,the instantaneous tripping current average for more than 7 ie,the action time of more than 150 ms,commonly used in 3 ie current fuses,the fuse for more than 50 ms,gmt32 miniature circuit breaker of the instantaneous tripping current for (2.8 3.5),the action time of 20 ms or less。
thus,internal resistance is small、the instantaneous tripping current small gmt32 miniature circuit breaker to reduce metering device voltage loop pressure drop、improve the measurement accuracy is indispensable。
gmt32 series miniature circuit breakers(hereinafter referred to as a circuit breaker),applied to ac 50 hz,below the rated current 10 a,rated voltage 230 v / 400 v of pt in the network,used to allocate electricity and as over-current protection circuit and power supply equipment,also can be used to frequent on-off operation。the circuit breaker has a small volume、high breaking capacity、nimble、low pressure drop, etc,therefore is particularly suitable for circuit breaker requirements small pressure drop、short circuit current action requires small pt line protection and precision instrument protection fast。
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