No

Device

Use

Effect

1

Fuse

To provide interruption of permanent faults.

Causes further expansion of voltage transient due to delay in melting.

2

Relay

To isolate or change the state of an electric circuit.

Inability to recognize whether the fault is internal or external.

3

Oil Circuit Breaker

For Insulation and heat dissipation in the transformer.

Causes insulation flashover.

4

Disconnect Switch

To disconnect the power system when a failure occurs

Results in an electric arc that interrupts and reignites.

5

Recloser

To safeguard essential loads and isolate line difficulty.

Prone to interruption of non-faulted circuits and worsens reliability.

6

Load Break Switch

To allow specified currents to be made or broken.

Lack of short circuit breaking capability results in load interruption.

7

Bypass Switch

To allow voltage regulators to be bypassed and isolated for repairs.

Initial swing of voltage outside the acceptable range.

8

Gang Operated Switch

To operate more than one phase of the circuit at the same time.

Loses alignment easily thereby swinging the voltages.

9

Transformer

To step up or down the voltage to balance safety and efficiency.

Re-closure operations and tap changing on transformers disrupt the current flow.

10

Capacitor

To resist voltage changes.

Results in voltage transient in switching operation.