SU438078A1 - Method for automatic voltage regulation at distribution network substations - Google Patents

Description

one

The invention relates to the field of automatic control of the mode of electrical networks.

There is a known method of automatically regulating the voltage at a substation of a distribution network connected to the power system through a communication transformer and containing a capacitor unit by controlling the communication transformer depending on the substation voltage of the load current network. This method does not provide the required accuracy of voltage regulation, since the control of the condensing units, if they are located at the substation, is carried out manually.

The purpose of the invention is to improve the accuracy of voltage regulation. This is achieved as a result of measuring the load current of the distribution network and the reactive current of the communication transformer and the emf proportional to the load current directed oppositely by the E.D.S. used to control the transformer of the communication math with the use of a substation and emf proportional to the reactive current of the communication transformer with the phase opposite to the phase of the substation voltage, and depending on the received signal, the capacitor unit is controlled.

The proposed method is illustrated in the drawing, where 1 is the regulator of the condenser unit; 2 is a device producing emf proportional to the current used in the voltage regulator of the transformer of the communication transformer; 3 - a device for generating emf proportional to the reactive current of the communication transformer; 4 - temporary software device for controlling the mode of a capacitor unit (CI); 5 - voltage regulator for the communication transformer.

The emf is proportional to the reactive current of the communication transformer, is introduced in series with the voltage supplied to the regulator's measuring unit with a phase that coincides with the voltage phase when the reactive power is transmitted through the communication transformer to the network. The phase voltage, proportional to the reactive load of the network, is inputted from

phase coinciding with the phase of the pair.

Voltage regulation is carried out as follows.

The criterion for the mode of a capacitor unit is a given reactive current through

communication transformer. This current is set by the time program by the temporary software device 4 or set in several steps depending on the load of any network element. If a

the capacity of the capacitor plant exceeds the local consumption of the reactive power of the substation, the capacitor unit participates in the reactive power balance of the nearest substations and through the communication transformer establishes some reactive current outputted beyond the limits of the substation.

The criterion for reducing the load on the load node is the growth of this current. If the reactive current delivered through the communication transformer exceeds a certain predetermined value, then by regulator 1 this is perceived as a decrease in voltage, and the power of the operating part of the capacitor bank decreases. If the current decreases, the power of the operating part of the capacitor plant increases.

In case the capacity of the condenser installation is mainly intended for covering local consumption, then reactive current through the communication transformer can flow from the grid side, i.e., with the phase changed against the first case. An increase in the reactive current flowing in the direction of the substation's lines will be perceived by the controller 1 as an increase in voltage and to be accompanied by an effect that reduces the power of the operating part of the capacitor unit.

Switching on and off the section of the condenser installation will to a certain extent be accompanied by a change in voltage on the node station tires. However, the final regulation on the buses of the substation will be carried out by a communication transformer, the regulator of which controls the voltage according to the load of the network. When choosing the load current applied to the current compensation device of the automatic voltage regulator of the transformer, the actual mode of the capacitor plant is taken into account.

As a device controlling the magnitude and direction of the reactive current flowing through a communication transformer, a conventional serial voltage regulator can be used. A current flowing through the current compensation device of the voltage regulator of the communication transformer with polarity opposite to the regulator of the transformer is supplied to one of the windings of the current compensation. In this case, the voltage supplied to the measuring unit of the regulator of the capacitor installation mode will be almost constant and this regulator will respond to the magnitude and direction of the reactive load current flowing through the communication transformer.

Subject invention

A method of automatic voltage regulation at a substation of a distribution network connected to the power system through a communication transformer and containing a capacitor unit, by controlling the communication transformer depending on the substation voltage and network load current, characterized in that, in order to improve accuracy, load current

the distribution network and the reactive current of the communication transformer and emf, proportional to the load current, directed oppositely by the e.e.d.S. used to control the communication transformer are summed with the voltage

the substation and with the emf proportional to the reactive current of the communication transformer with a phase opposite to the phase voltage of the substation, and depending on the received signal, control the capacitor installation.