Mid-set switch cubicle, ring main unit and high voltage switchgear

mid-set switch cubicle, ring main unit and high voltage switchgear

In power transmission and distribution equipment, it is often heard that power distribution equipment such as mid-set switch cubicle, ring main unit and high voltage switchgear. So what is the difference between them?

In short, the center-mounted cabinet is called the armored removable center-mounted metal-enclosed switchgear. It has a three-layer structure. The upper layer is the bus bar and the instrument room (separated from each other), the middle layer is the circuit breaker room, and the lower layer is the cable. room. Because the circuit breaker is in the middle, it is called armored removable middle-mounted metal-enclosed switchgear, or middle-mounted cabinet for short.

The ring main unit is a group of high-voltage switchgear installed in a steel plate metal cabinet or made into an assembling interval type ring network power supply unit. The electrical equipment belongs to the high-voltage switchgear cabinet. Its core part adopts load switch and fuse. It has the advantages of simple structure, small size, low price, improved power supply parameters and performance, and power supply safety. It is the load switch cabinet (including combined electrical appliances) in the medium voltage system.

The difference between mid-set switch cubicle and ring main unit:

1. With different shells, mid-set switch cubicle handcart type (removable) switch cabinets such as KYN28-12 (GZS1) high voltage switch cabinet shell, the ring main unit is a fixed switch cabinet cabinet;

2. The switches are different, the ring main unit generally uses load switches, and the mid-set switch cubicle generally uses circuit breakers;

3. For different purposes, the mid-set switch cubicle is usually the so-called KYN28 cabinet, handcart type high-voltage switch cabinet, which is generally used to protect the back-end transformer or other high-voltage loads. The ring main unit is mainly used for high-voltage power distribution, dividing one or two high-voltage power supplies into multiple high-voltage power outlets; mid-set switch cubicle is mainly used for high-voltage load protection. The ring main unit has two forms: air insulation and a fully enclosed inflatable cabinet. The air insulation uses ordinary SF6 load switches to connect to a set of systems through copper bars. The fully enclosed inflatable cabinet has special connection devices in addition to the power inlet and outlet lines, and the cabinet is connected to the cabinet. Then in a complete gas cavity, it is filled with SF6 gas.

High voltage switchgear can be divided into fixed type and removable type according to the structure.

There are mainly KGN and XGN series in fixed switch cabinets. The removable switch cabinet mainly includes KYN series; there is no isolating switch in the removable switch cabinet, because the circuit breaker can form a disconnection point after moving, so there is no need for an isolating switch.

High voltage switchgear is divided into incoming cabinet, feeder cabinet, voltage transformer cabinet, high voltage capacitor cabinet (GR-1 type), electric energy metering cabinet (PJ series), high voltage ring network cabinet (HXGN type), etc. according to their functions.

In other words, mid-set switch cubicle and ring main unit are just one of high voltage switchgear, and all high voltage power distribution cabinets can be called high voltage switchgear in general.