The main power station acts as a central hub, and the customer station connects to the low-voltage network. This station, distribution room, has high-voltage switchgear panels and a transformer for the low-voltage connection.

The distribution network can be overhead lines or underground cables, depending on where you live. In cities, we use cables, while in the countryside, we use overhead lines. We also set up different network designs to make sure you get a reliable power supply.

Planning the network is crucial to meet future electricity needs. There are three planning types: long-term, network, and construction planning. Long-term planning finds the best network setup and investments for the future. It considers future developments and matches them with expected electricity demand. Construction planning is the actual design and engineering work for circuits and substations. Design, installation, operation, and maintenance are key considerations for a power system, including distribution. Our goal is to ensure the network meets demand and is reliable.

Distribution System Planning
In planning a distribution system, it’s crucial to decide where the main power hub, called the load centre or primary substation, should be located. This decision, especially in densely populated areas, needs careful consideration and should be part of a long-term plan, like a 10-year strategy. The primary substation then supplies electrical energy to nearby customers through various outlets. Customer substations further transform the high voltage from the distribution network to a lower voltage (LV), usually below 1000V.

Basic Design Criteria for the distribution network, which supplies electricity through cables or overhead lines (OHL) at 22kV or 11kV, involve different configurations. Examples include single-end fed, double-end fed, and closed ring network arrangements. Customer substations typically have step-down transformers to lower the voltage. They may also include high-voltage circuit breakers and ring main units. Ensuring remote-control facilities are available enhances the security of the power supply.

In contrast to transmission networks, where a ‘N-1’ reliability concept ensures that a single component failure doesn’t disrupt electricity supply, distribution networks have varied designs based on the locations of customer substations. There are three main types: Single-end radial fed, where customer substations connect to the primary substation, has the lowest supply security. Any failure at a single point, leads to a loss of supply. The time it takes to restore supply after a fault depends on the repair time for that fault.