SU1467670A2 - Centralized arrangement for power system voltage and reactive power control - Google Patents

Abstract

The invention relates to devices for controlling the voltage and reactive power of a power system. The purpose of the invention is to reduce active power losses by optimally distributing reactive power between sources. For this purpose, using the storage units of the optimal power values of sources 28, the logical elements HE 29, AND 30 and OR 31, the optimum values of the reactive power sources when the voltage of the reference node deviates from that calculated by the device are determined, stored and used as tasks in jJHraax. management before the next recalculation. 1 il.

Description

The invention relates to devices for controlling the voltage and reactive power of the power system and is an improvement of the device according to the main circuit, St. No. 1103325.

'The purpose of the invention is the reduction of active power losses by optimal distribution of reactive power between sources. 10

The drawing shows a structural diagram of a centralized device for controlling voltage and reactive power.

¹ -15

The circuit contains a complete mathematical model (block) 1 of the electrical system, with the help of which the constants are then used, which are then used in the collapsed model, a memory block 2, in which the constants used for calculating the voltage are fixed, and block 3 for calculating the optimal voltage in the reference unit, unit 4 of information about the mode of the electric network necessary to determine the optimal voltage in the reference node, voltage sensor 5, comparison unit 6, threshold elements 7, output unit 8, pulse expander 9, logical element, ment I 10, b lock 11 for fixing voltage deviations during the previous control cycle, block 12 for fixing changes in total reactive power during the previous control cycle, block 13 for calculating the required 35 changes in reactive power, logic element NOT 14, memory block 15, in which the constants necessary to determine the share of power plants in regulation 40, a sensor 16 for reactive power consumption; power plant reactive power sensor 17, restriction entry signaling units 18, power plant optimal reactive power calculation unit 19, distribution unit 20, actual and set reactive power comparison unit 21, threshold elements 22, AND 23 logic elements, device output units 24, logical OR element 25, signal pulse expander 26, logic element NOT 27, block 28 for storing the value of the optimal source power, additional $$ logic elements NOT 29, additional logical elements AND 30, Modes OR gates 31.

Block 1, shown conditionally in the circuit, is a large computer, with the help of which the constants are calculated, which are used to calculate the optimal voltage and reactive power distribution. Block 2 is a memory that stores the constants included in the control used to calculate the optimal voltage. Block 3 is a functional converter, with which the voltage is calculated based on information about power flows along power lines adjacent to the reference node, information about the number of units operating in synchronous compensators mode, consuming active rotation power and weather data characterizing losses on the crown.

Block 4 characterizes the complex of meters with which the input information necessary for calculating the voltage (power flows, the number of units operating in synchronous compensators mode, etc.) is input into the block.

Block 13 is a processor that calculates the required increment of reactive power based on the voltage deviation 4U ¹ recorded in the previous ^one , the compensation of which required a change in power and information about the current voltage deviation AU according to the formula

0Q · = AU / IQ * / di 'in the sentence of constancy of the ratio AQ / ZLU in two successive control cycles.

Block 15 is a memory in which coefficients B are stored from the equations of relative loss increments <9 7G / E0. Block 16 is a measure of the total reactive power of the generating sources of the subsystem. Block 19 is a processor that solves a system of linear equations of relative loss increments relative to the reactive power of generating sources. The numerical settings of the generating sources for reactive power appear on the terminals of this block. Block 20 is a processor with which the required increment of reactive power, determined using block 13, is distributed between the generating sources in proportion to the settings previously calculated in block 19.

In the -statics, the measured values of the voltage and reactive power of the sources are within the dead zones of the device, determined by the threshold elements 7 and 22, and | θ signals are absent on the output blocks 24.

The device operates as follows.

Preliminarily, in block 1, the constants 15 are calculated that are used to calculate the optimal voltage and reactive power distribution.

The former are stored in memory unit 2, and the latter are stored in memory unit 15. On the basis of the variables coming from the information meters represented by block 4, the optimal voltage of the reference unit is calculated in the functional converter, which enters 25 to the first input of the comparison unit 6, the second input of which receives the actual voltage from the meter. When due to the dependence of the load on the voltage. Block 20 is started in order to eliminate the deviation. The comparison reactors 21 receive the values of the reactive power assignments from the OR elements 31 and the actual reactive powers of the sources from the sensors 17. When the reactive power assignments appear in the outputs of the block 20 in the next control cycle, these quantities go to the inputs of the OR elements 31 and are fixed in blocks 28 memorization. When the tasks do not change, there is no signal at the input of the logical element NOT 29, and the signal that appeared at its output through the AND 30 logic element allows the input to the logical element OR 31 to be received from the memory unit 28, where the previously calculated value is recorded. The value of the mismatch from the terminals of the comparison blocks 21 goes to the threshold elements 22. When the mismatch exceeds the threshold, the signal is transmitted through the telecontrol channels at the power station, where the set value for the deviation of the actual voltage from the set at the output of the unit 6 appears jg signal equal in value to their difference , which is supplied to the calculation unit 13 and to the deadband set by threshold 7, which then passes blocks 8 and 9, arriving at blocks 14 and 10.

In statics, the voltage is optimal and there is no signal at the output of block 6. In this case, there is no signal at the output of threshold element 7 and at the output of blocks 8 dd and 9. There is a signal at the output of block NOT 14, which triggers a distribution block 19, which calculates, based on the initial data from blocks 16-18, the optimal reactive power duration of generating sources. There is no signal at the output of block 13, and therefore, there is no signal at the output of AND block 10. This prohibits the operation of the block

20, which does not change the task of generating sources for reactive power. When the voltage deviates in the reference node, the signal at the output of block 14 disappears and the signal at the output of block 10 appears. In this case, the operation of block 19 ’is stopped, by which it is impossible to calculate the optimal distribution of reactive power when the voltage deviation of the secondary voltage regulator changes by one step.

The control signals through the OR gate 25 enter block 26, where they are stored for a time longer than the transient control process. In this case, the signal appears at the input of the logical element NOT 27 and disappears at the second input of the logical element And 23, stopping further control until the end of the first control pulse. After that, management continues. After the voltage is introduced into the dead zone of the centralized control, a signal appears at the output of block 14, and in block 19 the reactive power of the generating sources is recalculated, which can be used in the next control cycle.

Regulation on the basis of deviation of the actual reactive power from the set in the modes with the voltage of the reference node that does not go beyond the dead band of the device allows maintaining in the power system the modes with the optimal distribution of reactive power between the sources, which reduces the loss of active power.

Claims (1)

Claim A centralized device for controlling the voltage and reactive power of a power system, pr. St. No. 1103325, which differs from that, to the input of additional logic elements NOT, to the first inputs of additional logic elements OR and to the inputs of memory blocks of optimal power sources are connected the outputs of the block are growing, which, in order to reduce losses of active power by optimally distributing reactive power between, sources, it is equipped with two blocks for storing the values of optimal power sources, two additional logical elements AND, two additional logical elements NOT and with two additional logical elements OR, distributions, respectively, the second inputs of additional elements OR 10 are connected to the outputs of additional logical elements AND, the inputs of which are connected to the outputs of the aforementioned memory blocks and additional elements NOT, the outputs of additional OR elements are connected to the inputs of the second and third comparison blocks, respectively .