Protecting the Circuit in an Electrical Distribution System

In today’s world, it’s hard to imagine life without electricity. Electricity has spread to all but the most secluded areas of the world, and every modern establishment has an electrical distribution system that requires protection to ensure its safety. To do that, an engineer must consider every possible failure or overload situation that may arise in the future.

However, there is no fixed way of ensuring 100% safety. An engineer must keep themselves up to date on frequently changing codes and standards, and then use them to protect the circuits and create safe distribution systems.

There are two main objectives behind having a circuit protection system in place:

1) Effectively stop the spread of any condition or fault

2) To prevent or reduce the chances of power loss

A building’s electrical distribution system may face conditions like short circuits, transient surges, overloads, under/overvoltage, and more. It is vital to have a failsafe system in place beforehand.

Over Current Protective Devices (OCPDs)

OCPDs have been used in protecting the electrical systems since the later part of the 19th century. These devices act as the first line of defense against overloads and faults. OCPDs include circuit-breakers, fuses, and relays, and these devices are connected to power systems. When there is a condition like a short-circuit or an overload, the OCPD breaks the circuit.

Ground-Fault Protection

While overload and short-circuits can be contained effectively by OCPDs, they are not equipped to handle arcing-type ground faults. In the case of arcing-type faults, the fault currents are extremely difficult to detect because of their intermittent nature. For such conditions, an engineer must employ ground-fault protection systems.

There are two types of ground-fault protection:

A) Ground-Fault Protection of Equipment (GFPE)

This system is meant to protect the equipment against line-to-fault ground currents. GFPE is capable of sensing faults up to 30 mA and does not cover personnel.

B) Ground-Fault Circuit Interrupters

These devices are capable of detecting faults up to 5 mA. GFPE is used for electrical systems whose uninterrupted running is exceptionally vital, such as hospitals.

Why is Grounding Necessary For Power Distribution Systems?

Grounding a power distribution system is extremely important because:

– It can help negate the voltage surge caused either by lightning or due to sudden connection of supply conductors with high-voltage conductors.

– It stabilizes the operating voltage in normal conditions.

It ensures the safety of a power distribution system. An ungrounded system is unsafe and can be hazardous.

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