How are High Voltage Switchyards and Substations Helpful?
Switchyards and substations are significant components in the electrical generation, transmission, and distribution system. They deliver the transformation, switching, and protection of transmission and distribution systems.
What is “Switching Substation”?
A switching substation, also known as switchyard, is a substation without transformers that functions solitary at a single voltage level.
Switchyards are used largely for connections and interconnections and are important for transmission, distribution, and collection. Substations may be maintained and operated by an electrical utility or may be owned by a huge industrial or commercial customer. Normally, substations are unattended, depending on SCADA for remote supervision and control.
The purpose of the electric power delivery system is to transport electric power from generation sources to end users. Substations are the vital part of this electrical generation, transmission, and distribution system. Substations transform voltage from high to low, or the reverse, or perform any of several other important functions. They also provide the transformation, ties, switching, and protection of the transmission and distribution systems.
Key Elements of a Substation
Switches – These are the devices that connect and disconnect the current path
Protection and Control Equipment – This is an equipment to control substation equipment, send power from one circuit to another, or open or shut down circuits when needed
Transformers – They are the devices that transfer electrical energy from one circuit to another, without changing the frequency. They use electromagnetic induction; which is used to change the line voltage.
Circuit Breakers – These are the devices used to complete, maintain and interrupt currents flowing in a circuit under normal or faulted conditions
Substations use huge transformers to convert a generator’s voltage up to tremendously high voltages for extensive distribution on the grid.
What are the Elements of a Substation?
Substations usually have switching, protection and control equipment, along with transformers. Circuit breakers are used to interrupt any short circuits or overload currents that may occur on the network in the huge substation. Whereas smaller distribution stations may use recloser circuit breakers or fuses for protection of distribution circuits. The power plant may have a substation nearby, however, substations themselves do not usually have generators. The substation may also have other devices such as capacitors and voltage regulators.
Substations can be constructed on the surface in restricted enclosures, or under the ground, or can be located in specially designed buildings. Tall & huge buildings may have few indoor substations. Generally, urban areas mainly have indoor substations. The reason is transformers generate noise and switchgear needs protection from varying climate and pollution conditions.
A grounding (earthing) system necessitates designing. To prevent short-circuit in the transmission system, the total ground potential rise, and the gradients in potential during a fault (called touch and step potentials), needs to be calculated. A ground potential rise can be caused by earth faults at a substation. During a fault, in the Earth’s surface when current flows, it can cause metal objects to have a different voltage than the ground under a person’s feet; this touch potential presents a hazard of electrocution. The substation which has a metallic barrier should be suitably grounded to guard people from the hazard.
The main issues are reliability and cost. A good design tries to strike a balance between these two. It attempts to attain reliability without unnecessary cost. The design should also allow expansion of the station when required.
Apollo’s electrical engineering team designs and builds high voltage projects across India. They are specialized in electrical contracting services for switchyards and substations and high voltage transmission lines.
Contact Apollo for more information.