The use of current transformers

A) current transformer wiring should comply with the principles in series: the first winding in series with the circuit under test should be, while the secondary

winding of the transformer load current with all instrument series
2) Press the measured current size, select the appropriate changes, otherwise the error will increase. Meanwhile, the secondary side must be grounded at one end to

prevent the insulation being damaged, one side of the low pressure side of the high pressure fleeing into the secondary, resulting in personal and equipment accidents
3) Open the secondary side is absolutely not allowed, because once open, the primary current I1 all become magnetizing current, causing φm and E2 surge, causing

excessive core saturation magnetization, severe fever and even burned coil; while over-saturation magnetization of the magnetic circuit after , the error increases.

In normal operation the current transformer, the secondary side is similar to a short circuit, it is suddenly open, the value is very small excitation force by the

sudden change of the value of large value, the magnetic flux in the core presents a serious saturated flat wave, so the secondary winding of the magnetic induction

through zero

A very high spire wave, its value can reach thousands or even tens of thousands of volts, endangering the safety of staff and instrument insulation.
In addition, the secondary side of the open circuit voltage of the secondary side of several hundred volts, when it comes to electric shock. Therefore, the current

transformer secondary side switches are available in short, to prevent secondary side open. During use, the secondary side should immediately removed once the open-

circuit load, then

, And then deal with power outages. Everything handle before reuse.
4) In order to meet the measurement instrument, relay, breaker failure judgment and failure filtering device needs, generators, power transformers , outlet, bus section

breakers, circuit breakers, circuit breakers are located bypass 2 to 8 of the current transformer secondary winding

Makers.
5) For the installation of protective current transformer locations should try to eliminate the main protection device is not protected zone settings. For example: If

two current transformers, and the location permit, should be located on both sides of the circuit breaker, the circuit breaker is in the scope of cross-protection

among
6) In order to prevent pillar type current transformer bushing flashover caused by bus fault, current transformers are usually arranged in the circuit breaker or

transformer side outlet
7) In order to reduce the damage to the generator internal fault, means for automatically adjusting the excitation current of electric transformer shall be arranged on the

outlet side of the generator stator winding. In order to facilitate analysis and incorporated into the system before the discovery of the generator internal fault

current transformer used for measuring instruments

Device should be installed in the generator neutral point side.