LT Panel
Types of Components and Connection Diagram.
1 - LT Panel:
LT panel is used for distribution of 415 volt power supply.The LT power supply is received from two source,
one source is received from transformer outgoing 433 volt supply and other source is received from DG
synchronization panel. The LT panel power supply is distributed to the many feeders.
LT panel
image below
mentioned for reference.
2 - LT Panel Connection Diagram:
In this figure LT panel is connected to the two source one is transformer and other is backup source from 2 nos DG sets. After receiving the power supply is distributed into different outgoing feeders like as floor panel, WTP plant and chiller plant.
3 - Important Components of LT Panel:
1- Measuring meters.
Measuring meters are used for measuring the system parameters like as volt meter, amp meter, multifunction meter etc.
A- Digital Multifunction Meter
Digital multifunction meters are used for measuring the amp, current, voltage, energy, power factor etc. What is the multifunction meter , working principle and connection diagram?
B- Energy meter
Different different types energy meters are used for measuring the power like as 3 phase dual source, 3 phase single source etc. What is the dual source energy meter, working principle and connection diagram?
C- Analogue Amp and Volt Meter
Analog amp meter and volt meter are used on electromagnetic function. What is the Amp meter , working principle and connection diagram?
2- Indicator and Selector switches:
A- Indicators
Indicators are used for knowing the status of panel operation.Difference type indicators are used with different color.
- R Phase.
- Y Phase.
- B Phase.
- ACB ON.
- ACB OFF.
- ACB Trip.
- MCCB ON
- MCCB OFF
- MCCB Trip.
B- Selector Switches:
selector switch is used for auto and manual function.
3- Protection relays.
A protection relay is a automatic switching device which senses the abnormality in electrical circuit and provides a tripping signal to the circuit breaker for tripping resultant the rest Equipment remains safe.
Protection relay is used for LT panel safety which is installed in LT Panel as different types like as differential relay, reverse power relay, over voltage relay, under voltage relay and earth fault relay.
A- Differential relay:
The differential relay is commonly used in generators and transformers panel which is used for protection of
any abnormality in input and output power supply of DG panel or LT panel.
The main function of differential relay is to compare input and output current difference. If any side current
value is low or high as per set value then differential relay will be active and circuit breaker will be trip.
What is the differential relay, working principle and
connection diagram?
B- Over Voltage Relay:
OVR is a automatic switching device when senses any abnormality in voltage variation as per preset value then
it will provide
tripping signal to the circuit breaker so that system will safe.
Over voltage relay is used for protection against over voltage because due to over voltage the insulation may
be failure.
Over voltage relay is used in multiply of 5% voltage of 415 volt. It is used in LT panel or
isolation panel of transformer outgoing.
What is the over voltage relay , working principle and
connection diagram?
C- Under Voltage Relay:
UVR is a automatic switching device when senses any abnormality in voltage variation as per preset value then
it will provide
tripping signal to the circuit breaker so that system will safe.
under voltage relay is used for protection against under voltage because due to under voltage, the equipment
will take more current, resultant due to over current insulation may
be failure.
Over voltage relay is used in multiply of 5% voltage variation of 415 volt. It is used in LT
panel or
isolation panel of transformer outgoing.
What is the Under voltage relay , working principle
and
connection diagram?
D- Earth Fault Relay:
Earth fault relay is a automatic switching device which is used for sensing of current leakage as per preset
value of current leakage.
It is used in LT panel, HT panel and other electrical panel.
Leakage value of Current can be set 20% to
50% of equipment current rating.
What is the earth fault relay , working principle
and
connection diagram?
E- Reverse Power Relay:
RPR is a automatic sensing switching device which is used for protection of reverse power in DG incomer
panel.
When power supply is switched of then DG backup supply switch On during this period EB power supply completely
switched off otherwise any leakage current may be dangerous to the system. So the reverse power relay is used
for quick stopping reverse leakage current.
What is the reverse power relay , working principle
and
connection diagram?
4- Circuit Breaker:
Circuit breaker is used in LT panel for switching power supply incomer or outgoing feeders. Generally two types breakers are used in LT panel as ACB and MCCB.
A- Air circuit breaker (ACB):
This breaker is used in LT panel. It is works as a switching device manually or auto. It is used for control and protect of Electrical system from overload and short-circuit. In which breaker the air is used as arc quenching medium that breaker is called as air circuit breaker. What is the Air circuit breaker , working principle and connection diagram?
B- MCCB- Molded Case Circuit Breaker
MCCB Circuit breaker is used in LT panel for switching and controlling the power supply from overload and short-circuit. Generally it is used 100 Amp to 800 Amp in LT panel. It is installed for switching the power supply to the outgoing feeders. What is the molded case circuit breaker , working principle and connection diagram?
