Transmission switching is considered to be a creative electricity grid management system designed to take advantage of the electricity networks. Remember that you can switch in and out transmission lines out of the electricity network to enhance the efficiency of electricity generation on electricity networks.
Simply put, transmission switching is a controlling mechanism where line overloading and voltage capacity can be managed systematically, effectively, and profitably. Therefore, transmission line switching can improve your operational and economic efficiency. In this article, you will learn about the types of switches on a transmission line.
A switch
A switch refers to a device that can interrupt the movement of electricity through a circuit. Transmission towers and substations have switches, and to change how much current is flowing, you can open and close the switches. A switch can be used to switch transmission lines, allowing electricity to pass through power lines. You should note that a switch can only direct electricity.
Ideally, a switch functions by interrupting the electricity flow through a circuit. Therefore, when you open the switch current can flow through the circuit. On the other hand, the current cannot flow through the circuit when the switch is closed. This allows you to redirect the electricity in power lines.
It’s worth mentioning that a switch operator controls the switches. They can decide to close or open the switch to direct the current flow. A switch can sometimes be remotely controlled utilizing a computer. Quite often, they can be operated from control rooms that are located at substations.
A vital step in ensuring dependable and secure power is transmission line switching. You need to understand the transmission line process so that you can properly switch your transmission lines when necessary. Besides, you can know about the potential impact of transmission line switching on the local power grid.
Types of switches on transmission lines
You can find automatic and manual switches which are electrical devices designed to open and close circuits. You can use these switches to continuously carry current without overheating. Also, they need to have insulation and clearances for the standard circuit’s voltage. Circuit breakers and switches give a simple way of controlling the areas of breakdowns and automatic over-current protection. Some of the switches you can find on transmission lines include:
Disconnect switches
You can usually use a disconnect switch in a primary circuit, especially if the opening circuit is needed under voltage with no load or little current. They are designed to interrupt the exiting or charging current of lines. This switch is commonly utilized to disconnect off-circuit breakers, transformers, and branch lines where the current load may be broken.
You can find a variety of disconnect switches, classes, and ratings. You can operate a disconnect switch from the ground using a long-handed switch stick if there is a reasonable mounting height. You can also decide to install sectionalizing switches on the cross arms that carry the primary circuit. In such cases, you can use a switch stick that can be attached to the belt of a lineman to operate a switch.
Bypass switches
You can use a bypass switch at regulator and booster installations to offer a reliable and quick way of taking the equipment in or out of service. You can do this by de-energizing a feeder circuit and preventing winding burnout that can happen in open-circuit windings.
Gang-operated disconnects
You can use a gang-operated disconnect where there is more than a single phase of a circuit that requires it to be opened at the same time. The air brake is a type of gang-operated disconnect switch that you can find on the market. You can use these switches at substations to switch structures. They can also be utilized on the power lines to de-energize and energize transformer banks.
In some cases, gang-operated disconnects can be utilized for sectionalizing. They can be motor-operated, though they usually come with a switch handle so that you can operate them using your hand. This type of switch is a good option because you can operate it from the ground. In most cases, it allows you to restore the service in other parts of the electricity network without climbing a pole.
Keep in mind that contacts of disconnects need to be smooth and you should apply non-oxide grease on their surfaces. You also have to lubricate the bearing and the blades must be rigid enough to allow the right alignment of contacts. Also, you need to identify defective and broken insulators while carrying out your inspections and replace them right away.
Oil circuit breakers
An oil circuit breaker is designed to automatically open a circuit under load. The breakers are usually made and connected for a single or more automatic reclosing so that they can restore service quickly once a fault has cleared itself. You should note that they are primarily used in switching stations or substations where high-grade or high interrupting capacity service is needed.
A pole-mounted oil circuit breaker is also known as a reclosure, interrupter, and oil-circuit breaker. They are flexible to utilize on the low side of the step-down substation and a branch circuit that is connected to crucial feeders as well as for protecting critical loads and isolating line problems.
The reclosure can be connected to the power line and is usually closed. And, the trip coil comes in series with the contract and gets energy from the fault current. This can lift the armature as well as the movable contact of the interrupting elements by magnetic attraction. Once there is a fault, the circuit immediately opens and can automatically reclose in at least three seconds. And, if the fault is still there on the first interruption, then the reclosure can open the circuit for just a second and even for the third time.
But if the fault persists after this second and third interruption, then the reclosure system automatically resets. And, if there is still a fault after the third interruption, then the reclosure can open for the fourth time and lock open. In such cases, you need to reset the reclosure manually.
