power sub p1

TRANSMISSION SUBSTATION

is basically a hub that connects two or more transmission lines. Think of it as a crucial intersection on the electrical superhighway.

DISTRIBUTION SUBSTATION

acts as the crucial link between the high-voltage transmission grid and local electricity users. It receives power from transmission or sub-transmission lines

DISTRIBUTION TRANSFORMER

 It receives power from transmission or sub-transmission lines (e.g., 115 kV), then uses transformers to reduce this to a medium voltage

COLLECTOR SUBSTATION

is a type of electrical substation, particularly common in renewable energy projects like wind farms, that collects power from multiple generating units (like wind turbines) and steps up the voltage for transmission to the wider electricity grid.

CONVERTER SUBSTATIONS

as the "translators " of our electrical grid.

CONVERTER SUBSTATION

Their main job is to Efficiently switch electricity between Alternating Current (AC) and Direct Current (DC).

SWITCHING SUBSTATION

also known as a switchyard, is a type of electrical substation that primarily focuses on switching operations within a power system without changing the voltage levels.

SWITCHING SUBSTATION

It acts as a central point for connecting, disconnecting, and rerouting power lines and equipment.

Step up substations

 are essential components of the electrical grid, directly connected to power generating stations where electricity is produced at lower voltages.

STEP UP SUBSTATION

Their primary function is to economically increase, or " step up, " these generated voltages to much higher transmission levels

Step down substations

are the crucial middle-men that bridge the gap between the bulk power transmitted across vast distances and the localized power needed by communities

primary substation

are linked with bulk load centers alongside primary lines of transmissions.

secondary substation

are lined alongside secondary transmission lines adjacent to loads.

Distribution substation

are located near the end users

Distribution substation

transformers change the transmission or subtransmission voltage to lower levels for use by end

mobile substation

are only for a dedicated purpose and are temporary in nature i.e. mainly for giant constructions.

mobile substation

 supposed to fulfill power requirements of the under-construction structures.

industrial substation

are also known as bulk substations and are traditionally referred to as distributive substation.

mining substation

is of a distinct kind and is needed to be designed carefully as an increased level of precautionary safety measures are to be taken for the operation of its electrical energy.

mining substation

is dedicated for the control of electrical power supply from the surface to mine power station lying underground.

Converter substation

contain equipment that changes the frequency of current from higher to lower

Converter Substation

can also convert AC to DC or the reverse.

SWITCHING SUBSTATION

includes switching the power line without altering the voltages as they are placed in between the transmission lines.

Switching Substation

It also isolates the faulted portion of the systems and de-energize faulted equipment which helps the grid operate with stability.

Collector Substation

used in distributed power generation projects like wind farms, hydroelectric projects etc where power flow from multiple power sources can be collected and distributed to the grid by stepping up the transmission voltage

High Voltage Substation

69kV,115kV,138kV,161kV,20kV

Extra High Voltage Substation

345kV, 500kV,765kV

Ultra high voltage substation

1100kV, 1500kV

Direct current high voltage substation

250kV,400kV,500kV

outdoor substation

are constructed in the open air.

outdoor substation

These are also known as a 66KV substation, 132KV substation, 220KV substation, and 400KV substation

indoor substation

are generally of lower voltages and are built under a roof or closed compartment.

indoor substation

These substations are also known as 11KV substations and 33KV substations etc.

pole mounted substation

 is an outdoor sub-station with equipment installed overhead on H.pole or 4-pole structure.

Lightning arresters

are installed on the high-tension (HT) side to protect the substation from lightning strikes.

oil circuit breaker

installed on the low-tension (LT) side to automatically isolate the transformer during faults.

underground substation

are built in ground or subversive.

underground substation

These substations are built in congested places where building open air/outdoor substations are not possible.

MAIN TRANSFORMER

stepping up or down voltage levels without altering the frequency.

TRANSFORMER TANK

Protects core and windings from the external environment, serves as container for insulating oil

bushings

Made from porcelain or epoxy resin and provide a safe, insulated path for conductors connecting the windings to incoming and outgoing cables, while also forming a barrier between the terminals and the tank.

Terminals

are the connection points for incoming and outgoing cables, mounted on bushings

Heat

Transformer Power Loss Is Released As ____

Oil Conservator

Provides adequate space for oil expansion. Transformer oil expands and contracts with an increase and decrease in temperature.

EXPLOSION VENT

A metallic pipe with a diaphragm located above the conservator tank, serves as an emergency exit for oil and gases by rupturing at low pressure during internal faults to safely release pressure

BUCHHOLZ RELAY

Use in Oil Immersed transformers above 500kva, mounted on the pipe between the conservator and main tank.

BUCHHOLZ RELAY

They detect gases like methane, CO, and hydrogen formed during internal faults, and activate trip and alarm circuits to interrupt current flow and trigger the circuit breaker.

BREATHER

 ensures moisture - free air enters as oil expands and contracts with temperature changes.

BREATHER

It is attached to the air pipe, and the silica gel inside absorbs moisture from incoming and outgoing air to protect the oil.

CIRCUIT BREAKER

To protect power systems by automatically interrupting the flow of electricity when a fault or abnormal condition is detected.

EXTINGUISH MEDIUM

air, oil, vacuum, or sf6

EXTINGUISH MEDIUM

A substance used in circuit breakers to interrupt the flow of current by quickly extinguishing the electric arc that forms when contacts separate under load.

DEAD TANK AND LIVE TANK

TYPES OF CIRCUIT BREAKER USED IN SUBSTATION

DEAD TANK CIRCUIT BREAKER

HV circuit breaker that house the switching mechanism in a grounded metallic container, providing safety and reliability in electrical systems.

LIVE TANK CIRCUIT BREAKER

Where the switching unit is located in an insulator bushing which is live at line voltage. cheaper than dead tank and require less space.

DISCONNECT SWITCH

Also known as isolators or switch disconnectors, are essential electrical devices use to safely isolate circuits or equipment from their power source for maintenance and safety purposes

EARTHING SWITCH

To ground HV equipment, effectively neutralizing any residual electrical energy. Protective measures during shutdowns. Ensures no charge remains trapped within the equipment.

LIGHTNING ARRESTER

Protecting electrical equipment from damage caused by lightning strikes and other voltage surges.

LIGHTNING ARRESTER

Act as surge protectors, providing a low resistance path for the surge current to travel to ground

SURGE ARRESTER

Connected in parallel with the equipment they are protecting. When surge voltage occurs, the arrester's resistance decreases, allowing the surge current to flow through it to the ground instead of passing through the protected equipment.

decreases

When surge voltage occurs, the arrester's resistance __________

CURRENT TRANSFORMER

Type of instrument transformer designed to reduce high AC to lower, more manageable level for measurement and protection purposes.

Current transformer

step down high currents, standard 5A or 1A, for use in metering, protective relaying, and other applications.

POTENTIAL TRANSFORMER

Also known as voltage transformer are a type of instrument transformer use to step down HV levels to safer, more manageable levels for metering and protection devices

BUS

Aluminum Conductor Steel Reinforced

Aluminum Conductor Steel Reinforced

ACSR

bus

is a central conductor that serves as a common connection point for multiple electrical circuits

BUS

Main conductors that carry electrical power and connect various equipment like transformers, circuit breakers and transmission lines.

INSULATORS

Support and isolate electrical equipment from ground and other conductive structures, preventing unwanted current flow.

SWITCHGEAR

Encompassing a range of devices like circuit breakers, switches, and fuses that control, protect and isolate electrical equipment. To manage the flow of electrical power, enabling safe operation, maintenance and fault protection within a power network.

SUBSTATION BUS SCHEME

Is the arrangement of overhead bus bar and associated switching equipment in a substation.

BUS BAR

Allows for the efficient distribution and management of electrical power within the substation, connecting incoming and outgoing lines, transformers and other equipment

ISOLATORS

Isolator or disconnector is a piece of equipment that is used in electric devices and power systems with the main function of effectively isolating two different parts of an equipment

CIRCUIT BREAKER

Protective devices that interrupt current during fault conditions like short circuits or overloads. Essential for maintaining power stability, protecting expensive equipments

SINGLE BUS

Simplest and least cost of all configurations. Requires less area

SINGLE BUS WITH SECTIONALIZE SYSTEM

Incoming and outgoing circuits are distributed evenly on sections

The sectionalizer circuit breaker will enable bus differential protection to trip only the faulty section and keep the healthy section running.

MAIN AND TRANSFER BUS

Two buses, one main bus and the other transfer bus also called an auxiliary bus.

DOUBLE BUS DOUBLE BREAKER

There are two buses and two circuit breakers. Any circuit breaker can be removed for maintenance without interruption of the corresponding circuit. Also the failure of one of the two buses does not interrupt any circuit as all the circuits can be fed from the remaining bus and isolating the failed bus. By shifting circuit from one bus to other the loading on the buses can be balanced.

DOUBLE BREAKER BUS SYSTEM WITH A BUS SECTIONALIZER

Offers enhanced reliability compared to a single bus system by providing two independent buses and allowing for fault isolation.

DOUBLE BUS SINGLE BREAKER

Has two buses. There is one tie breaker between two buses.The tie breaker is normally closed. For the tie breaker in closed position the circuit can be connected to either of the buses by closing the corresponding switch. It is clear that fault on one bus requires isolation of the bus and the circuits are fed from the other bus.

RING BUS

Forms a Ring. There Are Isolators On Both Sides. any one of the breaker can be opened and isolated for maintenance without interrupting any of the circuits

ONE & HALF BREAKER BUS SYSTEM

Has two main buses. Three buses connected between the buses.

MESH BUS SYSTEM

A busbar arrangement where circuit breakers are installed within a meshed formed by the busbars, allowing multiple circuit connections and fault isolation.

When evaluating a double bus, single breaker scheme with a bus coupler, what happens if the bus coupler breaker fails during a bus transfer operation?

A major fault can span across both busbars if synchronization or interlocking fails, potentially leading to a widespread outage.

Which bus scheme offers a compromise between cost and flexibility, featuring two busbars where any circuit can be connected to either bus via disconnectors, but uses only one main breaker per circuit plus a bus coupler?

Main and transfer bus scheme

Which type of circuit breaker uses pressurized SF6 gas for arc quenching and insulation, known for its compact size and excellent dielectric properties?

Sulphur hexafluoride (SF6) circuit breaker

In a breaker-and-a-half scheme serving six total circuits, how many circuit breakers are required in total?

9 breakers

In a ring bus scheme, what operational advantage occurs if a single circuit breaker undergoes maintenance or fails to open during a fault?

Only the adjacent breakers trip, maintaining service continuity to the rest of the ring.

True or False: In a breaker-and-a-half scheme, each circuit is connected between two circuit breakers, meaning the failure of a single busbar does not interrupt power to any circuit.

true

A double bus, single breaker scheme offers which of the following operational advantages over a basic single bus scheme?

Flexibility to transfer circuits between busbars without interrupting customer load

Disconnect switches are typically interlocked mechanically or electrically with circuit breakers to ensure they are only operated when the circuit is carrying low current

true

A potential transformer (PT) must never have its secondary terminals short-circuited during operation, whereas a current transformer (CT) must never have its secondary terminals open-circuited.

true

A power substation experiences a severe fault on one of its outgoing transmission lines. Which primary component is responsible for automatically switching and interrupting the heavy fault current to isolate the affected section?

Circuit breaker

What is the function of a neutral grounding resistor (NGR) connected to the neutral of a power transformer in a substation?

To limit the magnitude of single-line-to-ground fault currents to protect equipment

Which substation component is installed directly beneath or near power transformers to catch and contain oil leaks and extinguish fires in the event of a catastrophic failure?

Oil containment pit and stone-filled gravel bed

What is the purpose of installing a surge capacitor at the terminals of large substation transformers or rotating machines?

To slope off the steep wavefront of incoming lightning or switching surges, protecting winding insulation

Which device is primarily used to step down high transmission voltages to safe, standardized levels for measurement, metering, and protection relays?

Potential transformer (PT)

In a ring bus scheme, if the number of lines and transformers is N, the number of circuit breakers required is also equal to N.

true

Which bus scheme utilizes two main busbars and two circuit breakers for every single circuit, providing the highest reliability and allowing maintenance on any breaker or bus without interrupting service or requiring bus switching?

Double bus, double breaker scheme