High Voltage Switchgear and Controlgear

In recent years, with the continuous development of society, economy, and switch technology, the complexity of engineering construction has increased, and miniaturized, maintenance-free, and intelligent switchgear products have become increasingly popular. Domestic and international switch manufacturers are vigorously developing medium-voltage gas-insulated switchgear (C-GIS), also known as gas-insulated switchgear. Gas-insulated switchgear encloses high-voltage components such as busbars, circuit breakers, disconnectors, and power cables in a housing filled with a low-pressure gas.

The company's design solutions can meet the requirements of various users in medium-voltage power distribution systems regarding ring network configurations, combination methods, operating conditions, safety protection, transportation, and installation. Extended busbars are used to connect the switchgear, achieving a fully modular configuration, thus satisfying various standard and non-standard power distribution schemes in the power distribution network.

01) Because sulfur hexafluoride gas with insulating properties is used as the insulating and arc-quenching medium, the size of the switchgear can be greatly reduced, making it more compact and miniaturized.

02) High reliability and safety: The conductive parts of the main circuit are sealed in SF6 gas, and the high-voltage live conductors are enclosed, unaffected by changes in external environmental conditions, enabling the equipment to operate safely for a long time, with high reliability and no risk of electric shock or fire.

03) Independent modular design, the gas box is made of high-precision aluminum plate and can be disassembled. The disconnecting switch adopts three-position linear drive. In order to reduce the complexity of control relays and wiring, a control module with nearly 100 points of matching PLC is designed to realize the electric remote operation of grounding and disconnecting switches. The mechanism switch is modularly designed, and the opening and closing points are connected with plum blossom contacts, eliminating the possibility of operation failure of the original rotary disconnecting switch and grounding switch. It also changes the problem of unstable and excessive contact resistance of the original rotary disconnecting switch. All contacts are equipped with shielding voltage equalization covers to solve the partial discharge problem in the production of switch breakpoints.

04) Convenient application and layout: Gas-insulated switchgear, as an independent unit, can be combined to meet various main wiring requirements. Delivering it to the site in unit form shortens the on-site installation period and improves reliability.

• GB/T11022-1999 Common Technical Requirements for High Voltage Switchgear and Controlgear Standards
• GB3906-2006 3.6kV ～ 40.5kV AC Metal-Enclosed Switchgear and Controlgear
• GB311.1-1997 Insulation Coordination of High Voltage Transmission and Transformation Equipment
• GB/T16927.1-1997 High Voltage Testing Techniques - Part 1: General Test Requirements
• GB/T16927.2-1997 High Voltage Testing Techniques - Part II: Measurement Systems
• GB/T7354-2003 Partial Discharge Measurement
• GB1984-1989 AC High Voltage Circuit Breakers
• GB3309-1989 Mechanical testing of high-voltage switchgear at ambient temperature
• GB4208-2008 Enclosure Protection Rating (IP) Code
• GB12022-2006 Industrial Sulfur Hexafluoride
• GB8905-1988 Gas Management and Inspection Guidelines for Sulfur Hexafluoride Electrical Equipment
• GB11023-1989 Test method for sulfur hexafluoride gas tightness of high voltage switchgear
• GB/T13384-1992 General Technical Requirements for Packaging of Mechanical and Electrical Products
• GB4207-2003 Method for determining the comparative tracking index and resistance tracking index of solid insulating materials under humid conditions
• GB/T14598.3-2006 Electrical Relays - Part 5: Insulation of Electrical Relays
• GB/T17626.2-1998 Electromagnetic compatibility testing and measurement techniques - Electrostatic discharge immunity test
• GB/T17626.4-2008 Electromagnetic compatibility testing and measurement techniques - Electrical fast transient/burst immunity test
• GB/T17626.5-2008 Electromagnetic compatibility testing and measurement techniques - Surge (impulse) immunity test
• GB/T17626.12-1998 Electromagnetic compatibility testing and measurement techniques - Oscillation wave immunity test

◆Insulation test

◆Temperature rise test

◆ Loop resistance measurement

◆Short-time withstand current and peak withstand current tests

◆Verification of closing and breaking capabilities

◆Mechanical operation and mechanical characteristic testing

◆Protection level testing

◆ Additional tests for auxiliary and control loops

◆Pressure withstand test of the inflatable compartment

◆Sealing test

◆Internal arc test

◆Electromagnetic compatibility test

Note: There should be no flammable gases, fire, or explosion hazards in the surrounding area. The severity class for condensation and pollution operation under GB3906 shall be Class 1.

C-GIS Gas Insulated High Voltage Switchgear has rated current levels of 630A, 1250A, 1600A, 2000A, 2500A, and 3150A. The cabinet dimensions can be customized according to requirements. The enclosure is formed by shearing and bending aluminum-zinc coated steel plates. The gas tank is welded with 304 high-quality stainless steel plates. Each unit is independently expandable and can be combined as designed. The cabinet is divided into the Secondary Control Compartment, Busbar Compartment, Circuit Breaker Compartment, Circuit Breaker Operating Mechanism Compartment, and Cable Compartment. The cable connection height can reach up to 700mm, facilitating maintenance and installation.

The cabinet features a complete grounding protection system. The switchgear cabinet consists of mutually isolated functional compartments such as the Switchgear Compartment, Busbar Compartment, Cable Compartment, and Secondary Circuit Channel. Each functional compartment is isolated by metal grounding partitions and operates independently.

1. Secondary Control Compartment
The Secondary Control Compartment is located at the upper front of the cabinet body. It contains component mounting boards and terminal block fixing brackets inside, which can be used to install connection terminals, small busbar terminals, comprehensive protection devices, and other control and operating devices to realize system remote control, remote measurement, telecommunication, and on-site monitoring functions. Circular holes for connecting busbars between cabinets are provided at corresponding positions on the left and right side panels, making wiring convenient. (Screenshot shows part of the secondary box body).

2. Busbar Compartment
The Busbar Compartment is sealed inside the upper gas tank and shares the same gas tank with the isolation mechanism. After the cabinet is placed on the foundation base, the left and right cabinet bodies and busbars are tightly connected together through the busbar connections between the panels.

3. Switchgear Compartment
The Switchgear Compartment is located in the middle section of the cabinet. This cabinet type adopts a plate-type gas insulated switchgear structure, arranged with upper and lower gas compartments. The upper gas compartment contains a three-position disconnecting switch, while the lower gas compartment contains a vacuum circuit breaker and busbars. The three-position disconnecting switch and vacuum circuit breaker are arranged "upper-middle-lower". The single-gas-compartment structure is simple to manufacture, low in cost, but places components together, making them susceptible to mutual influence and less reliable. The multi-gas-compartment structure allows for easier module replacement, avoids mutual influence between components, and features high safety, although the structure is complex and costly to manufacture.

4. Mechanism Compartment
The spring operating mechanism is arranged on a plane. The isolation mechanism and the circuit breaker mechanism are independently assembled. The mechanism and the vacuum interrupter insulation pull rod are assembled back-to-back, simplifying the transmission linkages, reducing power consumption, and improving mechanical reliability and flexibility. The output characteristics of the mechanism match the opening and closing characteristics of the circuit breaker better.

5. Cable Compartment
The Cable Compartment is located at the lower part of the cabinet and features an independent pressure relief channel. The height from the cable connection terminals to the ground can reach 700mm. Grounding interlocks can be installed in the cable compartment as required. Each circuit can accommodate two sets of cables and surge arresters. Furthermore, the incoming and outgoing cables and surge arresters adopt an inner-cone plug-in connection method.