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UNIT 6
TYPES OF ELECTRICAL POWER
DISTRIBUTION SYSTEMS

1 Learn the meaning of the following words, word-
combinations and word groups:
Phase voltage, neutral condition, earthing system, resistor,
reactor, insulation fault, occur, installation, tripping, exposed
conductive parts, dangerous potential, maintain, prevent,
appliance, enhance, safety, reliability, protect, low voltage
network, increase, flashover, winding, leakage, capacitance,
prevention, body impedance, resistance, earth fault loop, short-
circuit, destroy, special measures, damage, disturbance, switchgear
pole, tripping check, measurement, modification, extension.

2 Read and translate Text 1:

Text 1
Types of Electrical Power Distribution Systems

Electrical power is distribution either three wires or four wires
(3 wires for phases and 1 wire for Neutral). Voltage between phase
to phase is called Line Voltage and voltage between phase and
neutral is called Phase Voltage.
This fourth wire may or may not be distributed in distribution
system and the same way this neutral may or may not be earthed.
Depending on this neutral condition (earthed-not earthed-access-
not access) there are various types of earthing systems. The neutral
may be directly connected to earth or connected through a resistor
or a reactor. This system is called Directly earthed or Earthed
system.
When a connection has not been made between the neutral
point and earth, we say that the neutral is unearthed. In a network,
the earthing system plays a very important role. When an
insulation fault occurs or a phase is accidentally earthed, the values
taken by the fault currents, the touch voltages and over voltages
are closely linked to the type of neutral earthing connection.

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