The document outlines the objectives of relay coordination, including determining ratings and settings for breakers and relays to efficiently isolate faults and overloads. It emphasizes the importance of protective relays in maintaining electrical network integrity and ensuring proper coordination for primary and backup protection. Additionally, it discusses the applications of relays in isolating circuits, detecting faults, and controlling high voltage circuits with low voltage signals.

1. RELAY COORDINATION

2. Objective
• To determine the ratings and settings of breakers , relay, etc.
• To isolate the fault or overload.
• To identify the setting of the relay that can working at its efficient time to
clear the fault from the system.
• To create different types of electrical network which relay coordination is
tested with this network.
• To discover the impact of distributed generators to the protective relay
coordination on distributor network.
All the objectives above will be evaluated using IEEE C37.90
standard
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3. Why Relay?
• Relay is used to protect the electrical
network against the high voltage fault that
will happen in the system.
• Relay will work by sensing the fault
conditions and send the signal to the circuit
breaker to trip and close the breaker to clear
the fault .
• The relay circuit connection to the electrical
network plays an important role because it
will measure the electrical quantities which
are different for both normal and fault
condition.
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4. What Is Relay Co-ordination?
• The protective relay as primary and backup is
important in distribution system.
• A relay itself will be the primary protection to
protect its own system element and when to backup
other relays for fault at a location, it is serve to be a
backup relay.
• The protective relay should be time coordinated
with the other relay, so that the primary relay will
always operate faster than its backup relay.
• So, the coordination and setting of a relay is really
important to ensure which relay to operate first and
the other one stand for the backup protection.
• Therefore, the relay can perform both function
either as primary relay or backup relay for a remote
zone of protection
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5. Applications
 It isolates the controlling circuit from the controlled circuit when
the two are at different potentials.
 It is used in the Time delay functions.
 It is performed in logical functions.
 It detecting the faults on transmission and distribution lines by
opened and closed circuit brakers.
 It isolates the faults on distribution and transmission lines by
opened and closed circuit breakers.
 It is used to control high voltage circuits with the help of low
voltage signals
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