33KV Medium Voltage Gas Insulated System

Cotenele is an exporter of medium-voltage gas-insulated ring main units from China. Our newly developed 33KV Medium Voltage Gas Insulated System has been widely used by customers in Europe and Southeast Asia.

This rated voltage 40.5kv gas-insulated RMU, with its core advantages of compactness, reliability, and safety, has become a key equipment in the medium voltage distribution field, especially in scenarios where land resources are scarce, environmental conditions are harsh, and high requirements for power supply reliability are preferred.

This medium-voltage ring main unit complies with the relevant international and national standard such as IEC 62271,GB/T 3906-2020,DL/T 404-2018 ect.

Product Structures

The rated current levels of this gas-insulated medium-voltage switchgear include 630A, 1250A, 1600A, 2000A, 2500A, and 3150A, and the enclosure dimensions can be customized according to user requirements. Its enclosure is made of aluzinc steel plate through cutting and bending, while the gas tank is welded from high-quality 304 stainless steel plate. Each functional unit can be independently extended and combined into a switchgear assembly according to the circuit scheme.

The 33KV Medium Voltage Gas Insulated System can be divided into several separate compartments such as a secondary control compartment, a busbar compartment, a circuit breaker compartment, a circuit breaker operating mechanism compartment, and a cable compartment, where the cable connection height reaches up to 700 mm to facilitate convenient maintenance and installation. The complete switchgear is equipped with a full grounding protection system.

Moreover, the functional compartments, such as the switching compartment, busbar compartment, cable compartment, and secondary circuit channel, are isolated from one another, each separated by earthed metal partitions to ensure independence.

1. Busbar Compartment:

The busbar compartment is enclosed within the upper gas tank, which also houses the isolating mechanism. Once the switchgear is lowered onto the foundation base, the adjacent cabinet sections are joined together through a coupling process, thereby tightly connecting the left and right circuit units and their busbars into an integrated assembly.

2.Secondary Control Compartment:

The secondary control compartment is located directly above the switchgear enclosure. Inside, it is equipped with component mounting plates and terminal block fixing brackets, which can accommodate wiring terminals, small busbar terminals, integrated protection devices, as well as other control and operating components. This enables system functions such as remote control, remote measurement, remote signaling, and local monitoring. Circular holes for connecting small busbars are provided on the left and right side panels at positions corresponding to the terminals, facilitating convenient wiring when adjacent cabinets are coupled together.

Secondary control compartment

3. Switch Compartment:

The switch compartment is located in the middle section of the enclosure. This cabinet adopts a plate‑type gas‑insulated switchgear structure with two gas compartments, one upper and one lower. The upper gas compartment houses the three‑position disconnector, while the lower gas compartment contains the vacuum circuit breaker. The busbar, the three‑position disconnector, and the vacuum circuit breaker are arranged in an "upper‑middle‑lower" configuration.A single‑gas‑compartment design is simple in structure, easy to manufacture, and low in cost. 

However, because all components are placed together in one compartment, they are prone to mutual interference, resulting in lower reliability.In contrast, a multi‑gas‑compartment design allows for easier replacement of individual modules, avoids mutual interference among multiple components, and offers higher safety. Nevertheless, the multi‑compartment structure is more complex, more difficult to manufacture, and more costly.

4.Operating Mechanism Compartment

The spring operating mechanism is arranged in a flat layout, with the disconnector mechanism and the circuit breaker mechanism housed separately. The mechanism and the insulation pull rod of the vacuum interrupter are integrated in a front‑to‑back configuration, which simplifies the transmission chain. As a result, the output characteristics of the mechanism better match the opening and closing characteristics of the circuit breaker, reducing power consumption while improving mechanical reliability and flexibility.

5.Cable Compartment:

The cable compartment is located at the lower part of the switchgear and has an independent pressure relief channel. The height of the cable connection terminals from the ground can reach up to 700 mm. Grounding interlocks are installed inside the cable compartment as required, and each circuit can accommodate two cables and a surge arrester. Furthermore, both the incoming/outgoing cables and the surge arrester are connected using an internal cone plug-in connection method.