Why do telcos use DC power?

It prevents electrochemical reactions from destroying buried copper cables and rendering them useless if they happen to get wet. Negative voltage also protects against sulfation on battery terminals.

What is the function of DC voltage?

Direct current has many uses, from the charging of batteries to large power supplies for electronic systems, motors, and more. Very large quantities of electrical energy provided via direct-current are used in smelting of aluminum and other electrochemical processes.

What are the uses of DC power supply?

DC power is widely used in low voltage applications such as charging batteries, automotive applications, aircraft applications and other low voltage, low current applications. All solar panels nowadays produce DC power.

Why do we need negative DC voltage?

It is the highest, more safe that compromise voltage to pass over long wires. The negative voltage is used, so the current leaked due moisture does not electroplate away the copper, which is present in the cables.

What kind of voltage is used in telecommunication?

Volts direct current (DC) is used in telecom since alternating current (AC) just doesn’t fare well for voice communications. Meaning, you could expect hum, noise and numerous other issues using AC. Negative 48 volts direct current (-48VDC) is typically found on landlines in an idle state.

What is DC voltage source?

A dc voltage source consisting of two or more cells that converts chemical, nuclear, solar, or thermal energy into electrical energy. From: Modern Dictionary of Electronics (Seventh Edition), 1999.

Is DC voltage a sine wave?

DC circuits have a unidirectional flow of current and like AC it is not changing the direction periodically. Waveform of DC is a pure sine wave. As you can see, the voltage is constant with respect to time.

What is the use of DC supply in substation?

There is no big reason behind the uses of DC supply. The main reason for using DC supply in substation or power stations is to provide a continuous power supply to the control circuit. DC is a reliable source of power supply because it can obtain from batteries. Only a battery can give continuous power supply until it fully discharges.

What is the auxiliary supply voltage of a power substation?

Today, normal DC auxiliary supply systems in power substation are operating either on the 110 V or 220 V level, though lower levels exist. Some systems at the substation may require lower voltages as their auxiliary supply source.

What happens to the switchgear in a substation when power fails?

The control circuit for the switchgear system in a substation consists of many Circuit Breakers, isolators, Relays which are must be continuous ON condition. If we use AC supply which can not be obtained from the battery then we cannot provide the power supply to the control circuit during the power failure.

How many transformers are in a large distribution substation?

Large distribution substations have power transformers with a capacity as large as 100 MVA and serve as a source to as many as 10 distribution circuits. Read the difference between power transformers and distribution transformers.