SF6 Circuit Breaker (126kV) MLW36-126

Solutions

 

Application: For control and protection of 126, 145kV power system.

The circuit breaker is a design based on 3 porcelain-phase poles for outdoor installation, mounted on a circuit-breaker frame with racks. A 3-phase spring operating mechanism located in the center is installed in the switch cabinet. The circuit breaker is filled with SF6 gas and has the main function of extinguishing the arc in SF6 gas, for which the density monitoring device for SF6 is used to control the density and pressure. Thanks to the principle of using the stored energy and the optimized kinetic system of the circuit breaker, the device has improved mechanical efficiency and reduced energy consumption.

Features:

1. Reliable insulation performances.
2. Utilization of spring operating mechanism.
3. Low noise, easy or free of maintenance.
4. Easy installation and adjustment.

 

Design features

The switch has three poles. Each pole consists of a breaker, support insulator, insulating rods, etc. The interrupter uses the principle of extinguishing an arc by expanded gas, in which hot gas enters the thermal expansion chamber, forming a high-voltage gas when using arc energy when switching off high current. When a current exceeding zero blows the arc, hot gas quickly leaves the thermal expansion chamber. When a small current is disconnected, the gas compressed in the compression chamber extinguishes the arc. The breaker of each pole contains an absorbent to absorb moisture. The switch is equipped with a spring drive with a motorized platoon. The drive casing is mounted on a concrete foundation, in the upper part of the drive casing there is an arcing chamber.

 

Arc extinction principle

When the circuit breaker receives a trip command, the moving parts of the cylinder, movable arcing contact, rod, etc. move down under the influence of the breaking spring. The main fixed contact and the main movable contact open, and the two arcing contacts remain closed and current flows through them. Then the arcing contacts open, and an arc arises between them. Short circuit current significantly increases the energy of the arc; when the short circuit current is turned off, hot gas from the arc burning region enters the heat expansion chamber into the chamber and high pressure gas is formed. Since the pressure in the thermal expansion chamber exceeds the pressure in the compression chamber, the check valve closes. When the current passes through zero, the gas from the thermal expansion chamber is blown into the gap and extinguishes the arc.

During shutdown, the gas in the compression chamber is compressed and, when its pressure reaches a certain value, a spring valve opens, which protects against excess pressure in the compression chamber. When disconnecting small currents (below several amperes), the arc energy is small and, accordingly, the pressure in the thermal expansion chamber is low. The pressure in the compression chamber exceeds the pressure in the thermal expansion chamber. The non-return valve opens and compressed gas is blown into the gap. When current flows through zero, the blown gas extinguishes the arc.

 

Circuit breaker operation

Turning on

After the switching-on coil receives a switching signal, the switching-on latch works. The closing spring rotates the cam. The cam rotates the lever, which, in turn, drives the shaft, which completes the inclusion. In the process of switching on, the breaking spring is cocked by the connecting rod. After the shutdown is completed, the lever is fixed by the trip latch; the circuit breaker is in the off state and is ready to trip. The closing spring starts within 15 s after operation. Mechanical and electrical interlocks are used to prevent the drive from tripping again. At this moment, the switch is in the ON state.

Shutdown

After the trip coil receives a trip signal, the trip latch is activated. Under the influence of the breaking spring, the moving parts of the switch move down. When the trip is nearing completion, the drive’s oil shock absorber activates and absorbs the energy of the trip operation. In addition, at the bottom of the shutdown system there is a rubber shock absorber that acts as a disconnect gap.

 

Benefits:

1. High switching resource, high insulating properties
2. Reliable mechanical properties — less maintenance
3. Low noise
4. Easy to install, configure and test
5. Reliable seal system
6. Safe and reliable operation.

 

Dimensions (option 1)

Dimensions (option 2)

1. Pole (porcelain)
2. Base / Base
3. Density Monitor Pointer
4. Control cabinet
5. Nameplate (nameplate)

Please state the following when placing the order:

1. Title, model/specification of the product;
2. Rated voltage, rated current and rated control voltage;
3. Quantity of product and spare parts;
4. Other special requirements.

You can asking Data Sheet List before order by e-mail: power@mettz.com or mettzpower@gmail.com

Hot Tags: MLW36 sf6 circuit breaker, China, OEM supplier, manufacturers, factory, wholesale, sf6, circuit breaker, automation, breaker, retrofit

#mettz #mettzgroup #mlw36 #circuitbreaker #sf6 #breaker #retrofit #110kV