Electrical Distribution System from an 11kV Substation!!

An electrical distribution system is crucial for delivering power from a generation source to end-users. The schematic diagram you see illustrates the journey of electricity from an 11kV substation down to various sub panels. Let's break down each component along with its specifications to offer a clear understanding of the system:

Substation (11kV)

The journey begins at the 11kV substation, which serves as the primary entry point for the electrical supply. The substation has a fault level of 350MVA, indicating the maximum amount of power it can handle without risking damage during fault conditions. Essentially, it's like the main hub of power that prepares and sends electricity out to the next component.

11kVRMU (Ring Main Unit)

Next, the power flows into the 11kV Ring Main Unit (RMU). This unit is essential for managing the electricity that comes from the substation. The short circuit current at this stage is 18.37kA, which signifies the level of current that can flow during a fault. The 11kV RMU is connected to the main transformer through an 11kV HT cable of type 3CX185 SQ.MM, extending 25 meters in length.

Transformer (11/0.415kV, 1000kVA)

After the RMU, power passes through a transformer that converts the high voltage (11kV) into a low voltage (415V) suitable for use in buildings. This transformer has a capacity of 1000kVA. The short circuit current on this low-voltage side is 29kA, which reflects how much current can flow if there’s a fault. The transformer relays electricity through a main LT cable (Low Tension), which is 3CX300 SQ.MM, with a length of 70 meters.

Main LT Panel (415V)

The next stage is the Main LT Panel, which receives the converted power at 415V from the transformer via the LT cable. At this level, the short-circuit current is calculated to be 21kA. The main panel is responsible for distributing power to various sub panels, specifically Sub Panel-1 and Sub Panel-2.

Distribution to Sub Panels

Finally, the power is distributed to two sub panels: 

Sub Panel -1:

 - It receives power through an LT cable of type 3CX300 SQ.MM, measuring 80 meters long.

 - In case of a fault, the fault current here is 11kA.

- Sub Panel-2:

 - Although the specific cable details for Sub Panel-2 are not mentioned, it operates under similar principles as Sub Panel-1, facilitating further distribution of electricity.

This diagram effectively outlines the electrical distribution system from an 11kV substation to downstream panels. Each component has specific roles and is built to handle particular electrical loads, ensuring the safe and efficient delivery of power. This knowledge is essential for planning electrical systems, analyzing fault levels, and designing equipment that can sustain operational demands. Understanding these specifications helps maintain a reliable power supply for various applications.