RU1823071C - Electric substation compensator - Google Patents

Abstract

The inventive substation electrical compensator allows to increase the efficiency of the capacitors in various modes of operation of the substation, as required reactive or active power by connecting the three phases of the capacitors to the alternating voltage network and direct current through the relay monitoring the operation mode of the main network and thyristors, which instantly open this connection when a violation occurs, preserving the residual charge of the capacitors of each phase, taking into account the moment of occurrence on usheni and incorporated into the network d.c. together with the inclusion therein pushing load for the operational efficiency of the equipment chains compensated power substation. 1 silt

Description

The invention relates to electrical engineering and can be used in electrical networks to compensate for power.

The purpose of the invention is to increase the efficiency of using capacitor banks in both normal and emergency operation of the substation.

The drawing shows a diagram of the connection of phase capacitors to a DC and AC network in phase A.

The substation electrical compensator device contains a phase A capacitor 1 connected to a common point of the three-phase star circuit with its connection to the negative pole of the DC busbars of the substation, the second output of the capacitor 1 is connected to the positive pole by the make contacts of the command relay

turn on 2, as well as to the anodes of power drives 3 and 4 through the closing contacts of the voltage control relay 5, the coil of which is connected to the DC bus through the opening contacts of the relay for controlling the voltage reduction voltage 6 and the relay command switch 2. Relay coil 6 connected to the DC bus through a selective diode 7 and a differentiating capacitor 8. To the DC bus is also connected a circuit from a zener diode 9 and a resistor 10, the union point of which is connected to the control types of thyristors of categories 11, 12, an control which rows are connected to a capacitor 13, connected Shinko DC via an isolating diode 14. The cathode of the thyristor 11 is connected to polozhi00

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the direct pole of the DC busbars together with the cathode of thyristor 3, and the cathode of thyristor 12 is connected to phase A of the AC network together with the cathode of thyristor 4, which is shunted by diode 15 with the opposite polarity of its terminals.

Condensers of phases B and C 16 and 17 are connected in a similar way, and a three-phase rectifier 18 is connected to a constant load of 19 operational circuits, to which the jog load of 20 connections of the substation is connected by the relay contacts of the enable 2 command.

The device operates as follows.

Under normal operation of the substation and the rated voltage of the DC network, the relay 5 is in the actuated position, which provides the connection of the capacitor 1 with the AC and DC network.

With a variable voltage, the capacitor 1 is connected through the diode 15 in the forward direction and through the thyristor 4 in the opposite direction, therefore, the reactive power of the substation AC network is compensated. The coupling of the capacitor 1 through the thyristor 3 with a direct current network provides smoothing of the voltage from the rectifier 18 when operating on a constant load 19 of the direct current network. The symmetrical mode of the AC network creates the same conditions for all three phases without connecting the midpoint of the star of the capacitors to the neutral of the AC network and more efficient smoothing for DC busbars.

In violation of the normal mode of operation and a decrease in voltage from the circuit of the zener diode 9 and resistor 10, a control pulse of the thyristors 11, 12 arises, the unlocking of which causes the capacitor 13 to discharge by the inverse potential to the thyristors 3 and 4, which are instantly locked and maintain this state until transition of current through zero.

Within the specified time interval from the discharge current of the capacitor 8, a relay 6 is activated through the diode 7, causing a power failure of the coil of the relay 5, which disappears from the disappearance or reduction of the DC voltage. Falling of the relay 5 provides a continuous disconnection of the capacitor 1 from the AC and DC network for the entire time of a power failure of this network.

Depending on the moment of disturbance of the normal mode, capacitors 1, 16 and 17 store a charge in accordance with the voltage level of each phase. When the command to turn on the Jog load 20 is activated by closing the contacts 2, at the same time, the DC bus closes the circuit to feed them from the pre-charged capacitors 1. 16 and 17. In the normal operation of the substation, the contacts of the substation 2 open the coil circuit 5 and also make DC networks.

The separation diode 14 provides an excess voltage of the capacitor 13 in case of emergency voltage reduction in a parallel working AC and DC network, which creates the required

conditions for locking thyristors 3 and 4 immediately at the beginning of the voltage reduction.

Since the capacitance value of the capacitors 1, 16, and 17 is selected from the condition of complete compensation of the reactive load of the supply transformer of the auxiliary needs of the substation within its power, therefore, their immediate shutdown in case of violations in the supply network provides

a sufficient supply of energy for the operation of the substation equipment when switching on its operation commands.

As a result, the same capacitors D are normal for the substation

compensate the reactive component of the alternating current, and if necessary, the control equipment is fed with active energy for its more effective operation.

Form l invented and

Substation electric compensator containing capacitors in three phases of an alternating current network and between poles of a direct current network, from which

switching on the load of the operational circuits of the substation with the relay of the command Turn on the connections of the substation, with a three-phase rectifier between the AC and DC buses, different

5 in that, in order to increase the efficiency of using capacitors, the connection of the capacitors of each phase to the network is made through the closing contacts of the voltage monitoring relay, the coil of which

0 is connected to the DC network through the opening contacts of the relay to control the voltage reduction and relay contacts of the command Enable, the closing contacts of which are included in the combination circuit

5 phase capacitor with a positive pole of the DC busbars, to which a zener diode and resistor circuit are connected, the combining point of which is connected to the casing electrodes of the thyristors of the discharge capacitor of the control capacitor connected to the DC busbars through a diode, the cathodes of these thyristors are connected to the cathodes of the power thyristors in circuits for connecting a phase capacitor with a positive pole of a direct current network and with its phase of alternating current, moreover, a power thyristor

connected to an alternating current network, shunted by a reverse polarity diode, and the midpoint of a star of phase capacitors with a similar control circuit is connected to the negative pole of the DC busbars of the substation.