What is a Separator? What is it for, how does it work and what types are there?

Separator is a switching equipment used in electrical power systems to safely separate a circuit section from another section and creates a visible isolation distance in the open position. This equipment, also called Disconnector, is indispensable especially for maintenance and operational safety. Briefly, the answer to the question of what is a separator is; It is a switchgear that physically separates energy safely, allowing personnel to visually verify that there is no actual contact with the line.

The best answer to the question of what a disconnector is for is to provide safe isolation rather than disconnecting the load. If a line is to be maintained, a transformer cell is to be taken out of operation, or a busbar section is to be prepared for safe operation, the disconnector physically separates a certain part of the circuit from the network. This way, maintenance personnel can rely not only on the measurement, but also on the separation distance created by seeing the open contact gap. This feature is one of the cornerstones of operational safety, especially in MV and HV facilities.

The working principle of the separator is quite clear. In the closed position, the conductive path is continuous and the system is energized. When the opening command is given, the movable contacts of the disconnector are separated from the fixed contacts and a visible gap is created in the circuit. This gap is not just a theoretical break, but a truly traceable separation distance. For this reason, disconnectors have a different function than breakers in terms of maintenance safety. The breaker can interrupt the current, but the disconnector provides safe and visible isolation in the circuit.

The most important issue here is that the disconnector is not designed for on-off switching under load in the classical sense. Standard splitters are mostly operated in no-load condition. In other words, before opening the disconnector, no current should be carried in the circuit. Therefore, the separator and the breaker are not the same equipment. The breaker can interrupt the load current and short circuit current under certain conditions; The separator is mainly used to make safe separation in a circuit that does not carry current. This distinction is one of the most important operating rules in the field.

If there is a need for on-off switching under load, a load disconnector or, in appropriate cases, a breaker should be considered, not a classical disconnector. A load disconnector is a piece of equipment that can switch on and off normal operating currents, but is generally not designed to switch on short circuit currents like a breaker. Therefore, there are functional differences between disconnector, switch disconnector and breaker. In practice, mixing these three pieces of equipment can cause both equipment damage and serious safety risks.

In MV cubicles, the disconnector is a system element that often works together with the breaker, earth separator and cell interlocks. Particularly in metal-clad or metal-enclosed cells, the separator is an important part of the maintenance sequence. First, the breaker is opened, then the circuit is visibly separated with the separator, and then, if necessary, the earth separator is closed to create a safe operating condition for the line. This sequence is of critical importance for personnel safety, and mechanical-electrical interlock systems in cells are generally designed according to this logic.

Soil separator is an equipment that is mentioned together with the classical separator but has a different function. The classical disconnector separates the circuit, while the ground separator helps to safely discharge residual voltages or induced voltages by connecting the line confirmed to be de-energized to ground. Especially in MV and HV switchyards, simply separating is not enough; Grounding is also required in appropriate situations for safe operation. Therefore, separator and earth separator are considered together, but they are not considered the same equipment.

Separator types vary depending on the place of use. While indoor separators can be compact structures used in MV cubicles; Outdoor separators may have mechanical arrangements such as pole type, column type or center-hung. Single-pole, three-pole, horizontal or vertical expansion designs are selected according to the application in the field. In addition, in some facilities, separator solutions that can be operated remotely with a motorized control mechanism are also used. However, whether it is manual or motorized, the main function of the separator does not change: to provide visible isolation.

When selecting a disconnector, not only the voltage level but also factors such as rated current, short-term withstand current, dynamic resistance, contamination level, installation environment, locking structure and maintenance access should be evaluated together. Especially in outdoor applications, climatic conditions, ice load, pollution class and mechanical strength become important. In indoor cubicles, the compatibility of the equipment with the cell architecture, the mechanical relationship with the breaker and earth separator, and the operating sequence come to the fore.

Splitters are not protection equipment; The protection function is mainly carried out by relay and breaker chain. However, this does not mean that the separator is unimportant. On the contrary, if a disconnector is not operated correctly or its interlocks are not working properly, one of the biggest risks in the field arises. A structure that is operated in the wrong order, is forced to open under load, or operates incompatibly with the earth separator may cause harm to both personnel and equipment. Therefore, the separator operating logic must be supported by clear procedures in the field.

In maintenance and field applications, the contact structure of the separator, blade mechanism, hinge points, connection surfaces, motion transmission system, and if motorized, the drive mechanism and position indicators should be evaluated together. Visually obvious appearance alone is not enough; It should also be verified whether the contacts have actually reached the correct position, the locks are working properly and the auxiliary contact feedback is correct. Especially in old facilities, oxidation, mechanical clearance and contact surface problems can reduce separator performance.

The difference between a separator and a breaker is one of the most confused topics in the field. The breaker opens the faulty circuit with the protection relay command and can operate under load. The separator provides visible separation mainly for maintenance safety and is mostly used in unloaded operation. For this reason, it is not correct to think of the separator as a breaker and the breaker as a separator. For safe operation in an electrical installation, each piece of equipment must be evaluated in its role.

In summary, the separator; It is the basic switchgear equipment that provides visible insulation in electrical installations, enables maintenance safety and plays an important role in the operating chain between the breaker and the earth separator. It is designed for safe disconnection, not for tripping under load. Even though there are indoor, outdoor, earth separator or motorized types, their main function does not change. If disconnector selection, intra-cell operating sequence, interlock structure, MV/HV field suitability and switchgear equipment need to be evaluated together in your facility. HV/MV testing, maintenance and repair, on the project side LV/MV/HV project design and consultancy and business processes SA operation responsibility It is possible to progress in integration with services.