The primary function of the current transformer is to convert the large current in the AC circuit into a small current in a necessary ratio (the Chinese standard is 5 amperes) for accurate measurement and relay protection devices. In power generation, substation, transmission, distribution and distribution, due to the difference in electricity consumption machinery and equipment, the amount of current often ranges from tens of amps to tens of thousands of amps, and this power supply circuit may also vary with high voltage.
Then in order to better supervise and accurately measure the power circuit of this line, and at the same time to solve the risk of high voltage and high current, at this time, 180KW diesel generator sets need to use current transformers. A clamp meter for electricians, it is a kind of machine and equipment used to accurately measure alternating current. Its "clamp" is a through-core current transformer. According to the size of the measured current, select the appropriate transition, otherwise the error will increase. At the same time, one end of the secondary side must be grounded to avoid that if the insulation is damaged, the high voltage of the primary side will enter the low-voltage side of the secondary side, causing accidents to people and equipment.
The secondary side is absolutely not allowed to lead the way, because if it leads the way, the saturated state of the primary side current will become the magnetized current, the iron core will be magnetized in an over-saturated state, and the overheating will be serious and even the coil will be burned. At the same time, the magnetic circuit will be over-saturated state. After being magnetized, the error increases. When the current transformer is in normal operation, the secondary side is similar to a short circuit. If it leads the way suddenly, the excitation electromotive force will suddenly change from a small value to a large value, and the magnetic flux in the iron core will be severely saturated. Therefore, the secondary winding will magnetically induce a very high peak wave at zero time, and its value can reach thousands or even tens of thousands of volts, which is the safety protection of the workers in distress and the insulation performance of the instrument.
In addition, the lead of the primary side makes the voltage of the secondary side reach several hundreds of volts, which will cause a safety accident if touched. Therefore, the secondary side of the current transformer is equipped with a short-circuit switch to avoid the lead of the primary side. In the use of power distribution, if the secondary side leads the way, the power circuit load should be removed immediately, and then stop the vehicle to solve the problem. Any solution can be reused later.
In order to better meet the needs of measuring instruments, relay protection devices, circuit breaker failure identification and common fault filtering devices, 2 to 8 current transformers with secondary windings should be installed in generators, transformers, outgoing lines, bus sectional circuit breakers, bus circuit breakers, bypass circuit breakers and other circuits. For high-current grounding protection, it is usually configured in three-phase. For low-current grounding protection, it is configured in two-phase or three-phase according to actual regulations.
The installation address of the current transformer for maintenance shall be set as far as possible to eliminate the unnatural protection area of the main protection equipment. For example, if there are 2 sets of current transformers, and if the position allows, they should be installed on both sides of the circuit breaker, so that the circuit breaker is in the cross-type maintenance category.
Guangxi Dingbo Power Equipment Manufacturing Co., Ltd. is one of the earliest manufacturers of generators and diesel generator sets in China. The company was established in 2006 and the company occupies an area. With an area of 86,000 square meters and a building area of 45,000 square meters, it has service departments across the country to provide users with one-stop service of design, supply, debugging and maintenance at any time. Welcome customers to come to consult and visit. Looking forward to your inquiry, please send email to us for details email@example.com