Arc quenching suppression
Arc quenching suppression
Arc quenching suppression and elimination overvoltage switchgear.In the 3 ~ 35K V neutral point ungrounded system, the development process of single-phase grounding fault is generally: intermittent arc grounding → stable arc grounding → metal grounding. The overvoltage is the most serious when the intermittent arc is grounded, and the overvoltage of the non-faulty phase can reach 3.15~3.5 times of the normal operating phase voltage, or even higher.
Such a high overvoltage acts on the power grid for a long time, which will cause electrical equipment and electrical equipment. So Kaich has developed the third generation BWKX intelligent arc suppression and harmonic suppression and overvoltage protection
Application
- suitable for 3~35KV medium voltage power system
- suitable for the power system where the neutral point is not grounded, the neutral point is grounded by the arc suppression coil or the neutral point is grounded by high resistance;
- suitable for power grids dominated by cable lines, hybrid power grids of cables and overhead lines, and power grids dominated by overhead lines.
When the system is running normally, the open triangle voltage U△ is very small, and the controller panel shows that it is put into operation. Whether it is faulty or not is mainly judged by the open triangle voltage U△. When U△ changes from low level to high level, it indicates that the system has a fault. At this time, the microcomputer arc suppression controller starts immediately, and judges the fault type and phase according to the changes of the PT secondary output signals Ua, Ub, and Uc. , if phase A arc is grounded, order the vacuum contactor of phase A to close to the ground, and convert the arc phase to metallic grounding, then the arc of phase A is eliminated, and so on for phases B and C.
If it is a single-phase PT line fault, the device panel will display the fault phase and PT disconnection signal, and output passive contact alarm information.
If it is a single-phase metal grounding fault, the fault phase and grounding type signal will be displayed on the panel of the device, the vacuum contactor will not be closed, and the passive contact alarm signal will be output.
According to user requirements, the vacuum contactor can be automatically opened after the device operates for 5 s. If it is a transient ground fault, the system will return to normal; if it is a permanent ground fault, the vacuum contactor will not open again after the device operates again.
If the device is equipped with a dedicated small current line selection, when the PT open triangle voltage changes from low level to high level, the small current line selection module immediately collects data on the zero-sequence current of each line; if there is no single-phase grounding fault , it will return to normal; if a single-phase grounding fault occurs, the zero-sequence current of the line will be collected again after the faulty phase vacuum contactor is closed and the arc is extinguished. According to the principle of the largest mutation of the fault line after the grounding arc is extinguished, the fault line is selected and the fault signal is displayed on the panel, and the non-power switch contact signal is output at the same time.
Feature
1. The switchgear operates fast. It can operate within 30ms, which greatly shortens the duration of the single-phase grounding arc;
2. After the switchgear operates, the arc can be extinguished immediately, and the arc grounding overvoltage can be effectively limited to within √3 times;
3. After the switchgear operates, the system can be allowed to run continuously for more than 2 hours, and the user can deal with the faulty line after completing the switching operation of transferring the load;
4. The protection function of this installation is not affected by the scale and operation mode of the power grid;
5. The switchgear has high function and cost performance, and the voltage transformer can provide voltage signal to the meter and relay protection, which can replace the conventional PT switchgear
The main components and functions
B W K G is a powerful new type of high-capacity combined over-voltage protector, which plays the role of limiting the over-voltage of the system. It mainly has the following characteristics:
●Large current capacity, 2 m s square wave impulse current up to 1 0 0 0 A, better voltage limiting effect, wider application range, stronger tolerance, longer service life and can be applied to the protection performance requirements of the protector Higher special occasions;
●The voltage impulse coefficient is 1, the discharge voltage value is equal under various overvoltage waveforms, not affected by various operating overvoltages, the overvoltage protection value is accurate, and the protection performance is excellent;
●It is composed of zinc oxide non-linear resistance and discharge gap, which protect each other; the discharge gap makes the charge rate of zinc oxide zero, and the non-linear characteristics of zinc oxide resistance make the discharge gap operate without freewheeling and discharge. The gap no longer undertakes the task of arc extinguishing, which improves the service life of the product;
The four-star connection method can greatly reduce the overvoltage between phases (interpoles) and greatly improve the reliability of protection;
The valve plate and the discharge gap are assembled separately and do not affect each other. The discharge electrode is not easily affected by moisture and oxidation, which makes the action value more stable and reliable;
●BWKG overvoltage protector is the first device to limit all kinds of overvoltage in this device, which limits the voltage within the safe range before the contactor JZ does not act.
One end of the vacuum contactor is connected to the busbar, and the other end is directly grounded. During normal operation, J and Z are in an open state and are closed under the control of the controller K, C, Z, and K. The operating circuits of the vacuum contactors of each phase are mutually blocked. When any one of the phases is closed, the After the phase bus is grounded, any of the other two phases will not operate.
The function of J Z (A, B, C) is to quickly change from unstable arc grounding to stable metallic direct grounding when arc grounding occurs in the system, thereby protecting the equipment and preventing damage to the system and equipment.
The controller K C Z K is the core control part of the device. It judges the fault type (PT disconnection, metal grounding and arc grounding) according to the signals of U a o, U bo, U c o and U△ provided by PT, and controls the high-voltage vacuum quick contactor JZ according to the preset method.
When a single-phase grounding occurs in the protected system, the voltage U△ across the open triangle of the voltage transformer P T immediately changes from a low potential to a high potential, so that the controller is put into operation.
The high-voltage flow-limiting circuit breaker is the backup protection device of the whole device, which can prevent phase-to-phase short circuit caused by misjudgment caused by wrong wiring or device failure, and avoid causing more harm to the system
Use environment
1. Temperature: indoor type -15°C~+60°C, special can achieve -30°C~+60°C; outdoor type – 40°C+60°C.
2. Altitude: <2000m, if you have special requirements, please specify when ordering;
3. Use environment: There should be no explosive mixtures such as dust, dust, gas, flue gas, etc.