SU785940A1 - Method of regulating reactive power of rectifier-converter substation - Google Patents

Description

(54) METHOD FOR REGULATING REACTIVE POWER OF S1-DIRECTIVE-INVERTORY SUBSTATION

one

The invention relates to the field of power management and can be applied to control the reactive power of DC transmissions or rectifier-inverter substations (VIPs or DC-inserts).

The DC injection is a rectifier-inverter substation (VIP), performed on controllable gates and designed to provide flexible communication between power systems. A rectifying-inverter substation is capable of operating with a constant active power, as well as changing the transmitted power according to a predetermined schedule or by commands of automatic devices, regardless of the ratio of frequencies in the starting and receiving power systems.

When the power is changed, the reactive power consumed by the converters and the voltage level on the buses to which the converters are connected change.

A device for maintaining the voltage level fj is known.

This device implements a method of regulation, according to which the value of a given constant value

the current varies with the voltage fluctuations of the network. In this case, the active power transmitted will also be transmitted, which is a disadvantage.

Modern DC substations are equipped with devices designed to compensate for reactive power and allow it to be regulated without changing the active load.

10 Regulation may be aimed at maintaining the setpoints or the voltage or reactive power of the substation.

It is also known a device 2j, a reactive method of controlling reactive power, carried out by acting on ignition advance angles and a step switch for regulating the capacity of a capacitor battery, and reducing the reactive power consumed by the inverter substation leads to an increase in angles and avoiding the optimum mode, and also a reduction in the capacity of the capacitor battery, which is a disadvantage.

There is a known method of controlling reactive power, in which regulation is carried out by influencing the ignition advance angle and the excitation current of synchronous compensators installed at the inverter substation. At the same time, a decrease in reactive power consumption first causes an increase in the ignition advance angles of the inverter, then a decrease in the excitation current of the synchronous compensator, and then again an increase in the ignition advance angles of the inverter. The increase in reactive power consumption is accompanied by a decrease in ignition advance angles, an increase in the excitation current of synchronous compensators, and then again a decrease in the advancing angles p. In power systems, the requirements for maintaining reactive power on lines of communication with power systems with a dead zone for controlling reactive power are often asked. Under these conditions, when controlling reactive power with a dead zone, the control system comes into operation only with an increase in reactive power above the upper limit of the dead band or a decrease in reactive power below the lower border of the dead zone. When the reactive power is inside the dead zone, the inertial control system is valid. The disadvantages of this method are the ambiguity of the distribution of reactive loads between sources at the substation and, as a consequence, in a number of modes, the unreasonable loading of synchronous compensators with reactive power. According to the well-known method 3j, control of sources (consumers) of reactive power (synchronous compensator and control of the MbiM converter) is carried out in the presence of a deficit or excess of reactive power, i.e., a dead zone. One of the measuring bodies ensures control of the reactive power of the substation with a protected setpoint or with or without a dead zone. When controlling the reactive power of the VIP, in accordance with the proposed method, the change in the load of synchronous compensators, depending on the magnitude of the reactive power of the line inside the deadband, may be equal to the width of the deadband of the reactive power control system. So, with the width of the deadband of 50 MWar, the change in the load of the synchronous compensation of the torus can reach up to 100 MWAR. The aim of the invention is to increase the efficiency of the rectifier-inverter substation and reduce power losses in the substation. This is achieved by implementing the method of controlling reactive power of a rectifying inverter substation containing a reactive power regulator of a substation, a synchronous compensator with a regulator connected to substation buses, channels of measuring the reactive power of a line and synchronous compensators, consisting of measure the reactive power of the line and the synchronous compensator and, depending on the measured power, affect the excitation of the synchronous compensator, additionally the measured the reactive power of the Qnp converter is compared with the boundary values mi-reactive with the powers of the deadband QO + -5uQ and, where Q (j is the reactive power in the middle of the deadband, and dS is the width of the deadband, and when Q tip QO includes the power line, with a setpoint O.S, A Q and effect the regulator of the synchronous compensator, when PR QO disconnect the channel measuring the reactive power of the line and turn on the channel measuring the reactive power of the line with setting QO + - q Q and influence on the regulator of the synchronous compensator. With this method of controlling the reactive power of the substation, the synchronous compensator carries a lower reactive load. Fig. 1 shows a diagram of the change in reactive power of the synchronous compensator O.c (, depending on the reactive power of the QU line at a constant reactive power of the converter and the control of the reactive power of the VIP in accordance with the known method 3; 1 in Fig. 2 is a diagram of the reactive power of the synchronous the compensator and the reactive power of the line when controlling the reactive power of the line according to the proposed method; FIG. 3 is a diagram of the device implemented in the proposed method. The diagram (FIG. 3) contains the device 1 - regulator reactive power torus consisting of the following units and blocks: block 2 - converter of input currents and voltages of the VIP communication line with the power grid into a signal of reactive power connected to blocks 3, 4, 5 Г blocks 3 and 4 are forming blocks the signal of the reactive power deviation of the line from the task with the settings Qj- and Qj Q-, respectively (5 - jAQ, associated respectively with blocks b, 7, and 8, 9; blocks 6, 7 and 8, 9 are keys controlled from block 10 and associated with devices 11 (keys b and 8) and 12 (keys 7 and 9) j device 11 is a reg l Torr extinction angle (ORUP) and device 12 - an excitation regulator of synchronous compensator (ARVSK) J portion 13 -preobrazovatel currents and voltages of the synchronous compensator for reactive power signal associated with the blocks 5, 14, 15 and 16; block 5 is an adder whose input is connected to the outputs of line reactive power converters and a synchronous compensator and which forms a signal of the reactive power of the converter, the output of block 5 is connected to block 10; block 17 - transformer of current and voltage of synchronous compensator converted into corresponding signals, block 17 is connected with inputs of blocks 15 and 16; block 15 is a detector of the presence of the limit mode of the synchronous compensator, the output of block 15 is connected to the input of block 1, block 16 is a measurer of the deviation of the parameters of the synchronous compensator (CK) from long-term allowable, the output of block 16 is associated with block 18, block Blocks 14 and 18 are keys connected through a control input to block 10 and connected to an input of device 12, block 10 is a logic device that is connected to inputs 5 and 15 and whose output is connected to control inputs keys (6), 7, 8, 9, 14, and 18. In those cases x, when Qnp QO 2 (FIG. 2) and there are no limit modes of the SC, a logic device (block 10 holds the open key (block) 9, the other keys (blocks) 6, 8, 7, 14 and 18 keeps it closed. At the same time Maintaining the reactive power of the line with a setpoint equal to Qo-4-uji, affecting ARVSK 12. (Mode D in Fig. 2). With Qnp and the absence of limit modes, the SC logical device (block) 10 holds key 7 and keys 6 8, 9, 14 and 18 closed. In this case, the reactive power of the line is maintained with a setpoint equal to the impact on ARVSK 12. (Mode 11 in FIG. 2). At 4 (i | iA, the logic device keeps the key 14 open, and the remaining keys 6, 8, 7, 9, 18 are closed. In this case, the reactive power of the line is not maintained, but changes in accordance with the change in Q and is maintained at zero reactive power of the synchronous compensator Q by affecting ARVSK 12. (Mode W in Fig. 2). If 4 QQ - - | d Q and the synchronous compensator is in the limit mode for issuing reactive power, in this case the logical device 10 keeps the keys 8 open and 18, and the rest of the keys (b, 7, 9, 14) closed while maintaining The reactive power of the communication line with the power system with the QQ-- iQ setpoint by affecting the ROPP 11 simultaneously maintains the maximum IC output mode for the reactive power of the ARVSK 12. (Figure 2). If (lpp ii-fjiQ and synchronous compensator is in the limiting mode for the consumption of reactive power, then in this case the logical device 10 keeps the keys 6 and 18 open, the rest of the keys (7,8,9,14) closed. At the same time, the reactive power of the communication line with the power supply system with the setpoint i is maintained on the OSRUP 11 is maintained, while the maximum consumption of reactive power is maintained by the IC mode by affecting ARVSK 12 (mode I in Fig. 2). case when Q 0. Then with. supplying the reactive power of the VIP to the value greater than DC, the regulation of the reactive power of the communication line with the power system is carried out with the + L0 setpoint and when the reactive power is consumed by the converter, filters and capacitors by batteries smaller than DC, the reactive power is adjusted with the setpoint - DC1, and at values of the total reactive power of the converter, filters, and capacitor batteries in the + AQ range, is maintained by affecting the ARVSK zero reactive load of the synchronous compensator. In the latter case, the total reactive load of the blocks, filters and capacitor batteries is within + d (1, when the reactive power is consumed by the converter, filters and capacitor batteries, it is covered by the power system, and when issued it is transmitted to the power system. reactive power of the line within specified limits. In cases where the reactive load of converters, filters and capacitor batteries is greater than QQ-I-AQ, a part of the reactive power, namely QQ + AQ, is output via the power line, and the rest is consumed by a synchronous compensator. In cases where the load on converters, filters and capacitor batteries is less than Q, is D Q, a part of the reactive load, namely uQ, is consumed from the line and the rest is provided by a synchronous compensator. The reactive power of the TTI can be used both on the inverter side and on the rectifier side of the VII. When using the proposed reactive power control method, the efficiency of the rectifier-inverter operation increases NoL substation due to a decrease in the reactive load of the synchronous controller.

Claims (3)

1.naWHT FRG No. 892160, 21 d, 45/01, 1952. 2. Patent of Sweden No. 314430, cl. 21 s, 67/10, 1966. 3. USSR author's certificate for application number 2503763 / 24-07, CL, H 02 P 13/16, 1977 (prototype). (rig. 3