Automatic connectionThe automatic reclosing, or automatic reclosing switch, is a means of electroautomatics that is responsible for turning on the switched off switches after a certain period of time. APVA is divided into several types by the number of actions. There are single, double, triple switches, but there are also systems that include an eight-fold cycle of the device.

Content

  • 1 Main uses
  • 2 Classification device automatic reclosing
  • 3 The principle of operation of the device AR
  • 4 Basic requirements for the automatic reclosing device

Main uses

In electrical networks all damage types can be divided into two groups:

  • resistant;
  • unstable.

Resistant types include damage to the electrical network, which does not repair on its own after a time. To eliminate them requires the help of specialists, or rather, the emergency brigade. Such damage most often includes broken wires or damage in the line section, due to which further operation of the power grid is impossible.

Damage of unstable type characterized by recovery

voltage some time after the breakdown. For example, such a breakdown may occur after the wires collapse, and an electric arc arises, which does not cause significant damage to the electrical network. Due to the small amount of time during a short circuit, the entire circuit of the power grid is under relay protection. In practice, the amount of unstable damage is about 50–90% of all breakdowns electrical network.

Automatic reclosingAfter a breakdown, the automatic reclosure is responsible for re-enabling the network section. Repeated automatic power-up can be both successful and unsuccessful. If the voltage is restored after a breakdown, then the problem can be attributed to an unstable type. If the voltage during the automatic reclosure is not restored after a short period of time, it means that the type of damage is stable.

Solving the problem is possible even without the presence of the system, but this device is responsible for speeding up the recovery process, as well as fully takes on automation work.

The system of the automatic reclosing and automatic reclosing system and the APVA is widely used and is used in electrical networks and substations. The device is combined with other types of relay automation, which allows you to fully automate the work on substations, while eliminating the need for the use of an operational worker directly at the facility electrical network. Also, the use of an automatic reclosing device at substations makes it possible to avoid the error factor when operating personnel.

As stated in the EIR, the automatic reclosing device must be used on all cable-air and overhead lineswhich have an operating voltage of 1 kV or higher. Additionally, a transformer can be equipped with an automatic reclosing system. electric motors, as well as busbars substations.

Classification device automatic reclosing

Apva can divided into several types depending on the number of phases:

  • single-phase auto-reclosing - switch on only one phase when tripping due to short circuit
  • three phase system - includes three phases in the circuit
  • combining automatic reclosing - includes circuit sections with one or three phases depending on the damage to the power grid

AR devices with three phase type classified into:

  • simple (TAPV)
  • non-synchronous (NAPV)
  • high-speed (bapw)
  • responsible for checking the presence of voltage (APVNN)
  • responsible for checking the absence of voltage (APVON)
  • responsible for synchro expectations (APVOS) or synchrophase trapping (APVUS)

The principle of operation of the device AR

The scheme of application of the device may be different depending on the specific case. In automatics it is applied principle off VL with a voltage below 220 kV, and more precisely, the device checks the status and position of the switch key. More precisely, if the device received a signal about the absence of voltage, but the switch is in the on state, it means that an unplanned type power outage has occurred. This principle of operation allows us to divide the problem and in the event of a planned voltage shutdown, the automatic reclosing device or APVA simply does not respond.

Basic requirements for the automatic reclosing device

To ensure reliable voltage to the systems of the device AR a number of mandatory requirements. These include requirements:

  • Device requirementsThe system is obliged to trigger when problems arise on the network section that is under protection.
  • The automatic reclosure system is required to operate only after a certain period of time, if the voltage is turned off immediately after turning on the switch key. If the device is triggered immediately, then there is damage to the mains line, and a sudden switching on of the voltage with the help of automatic reclosure only aggravates the situation.
  • The device circuit should have an automatic blocking in the event that additional sources of protection are activated (gas protection of the transformer).
  • Automatic reclosing should work only in the specified frequency rate. More precisely, single-shot automatic reclosing should work once, double devices, 2 times, etc.
  • After the system is activated and the voltage is restored, the healthy system returns to the ready state.
  • The automatic reclosure should work only after a set period of time, which is usually 0.3–0.5 seconds. In some cases, the device slows down to a few seconds.