SU1277297A1 - Method of controlling power transfers in power grid - Google Patents

Abstract

This invention relates to the field of electrical engineering. The purpose of the invention is to increase the reliability and cost-effectiveness of the combined power grid by increasing the selectivity of controlling power flows with unbalances in power. Based on the measurement of the balance of power flows of each power system, comparing it with a predetermined value, a control signal is generated to control power plants. The control signal includes at least a proportional and integral component. The detuning of the control action in case of power imbalances in adjacent power systems is carried out by fixing the signs of the deviation signals of the I balance of flows of each energy system (L themes and derived frequency on the buses of each power system and excluding the integral component of the control signals, 2 or 3 signals. you to with

Description

The invention relates to power engineering and can be used to automatically regulate the flow of power along power lines between power systems. The purpose of the invention is to increase the reliability and efficiency of the combined energy system by increasing the selectivity of regulating the flow with unbalance of power. FIG. 1 is a diagram of the integrated power system; in fig. 2 diagram of the device for implementing the method. The interrelation between the signs of the signals of deviation of the balance of power system flows from a given value and the derivative of the voltage frequency to the power system bus is established as a result of considering the processes of changing power along the transmission lines (PTL) and voltage frequency when the unbalanced active power is in the integrated power system circuits (Fig 1) The integrated power system consists of three power systems connected by intersystem power transmission lines. The first power system is transceiver, the second is transmitting, the third is receiving. If there is a shortage in the first energy system, the fats up to overflows through external communications of this energy system change by values (the positive direction is the flow direction to this energy system). .LRp1. where is the change in the balance of flows of the first power system; RR is the change in the flow across line L,; DR is the change in the flow through the line, according to the law of distribution of the primary unbalance DRR, 1g O, dR, O i.e. DR 0. At the same time, it is obvious that Af O. For the second power system, when there is a deficit in the first balance of external power flows, it changes by the value where CRP,, aPn, -i is the change of power flows along the lines L, g and L For the second power system, we have LR, 0, d 0 Similarly, for the third power system, with a deficit in the first power system, it is not difficult to get LR with O, 4f, 0. When there is an excess of active power in the first power system, the change in sal-power is, before power flows through external communications, dR O at. In the second and third power systems with this dR. O with lR O with / 4f, 0. It should be noted that processes are considered here at the initial stage after the formation of a deficit (excess) of active power. In large power interruptions, the steady state frequency deviation after power imbalance is insignificant. However, at the first stage of the process, after a disturbance is applied to the system, the frequency deviation is several times higher than its steady state value. A clearer fixation of the voltage frequency change can be made by determining the time derivative of this parameter. Based on the analysis performed, it can be concluded that in the power system, in which there is a shortage (excess) of power, the signs of a change in the balance of power flows to external: in earth and frequency deviations and its derivative are different for adjacent power systems, these signs are the same. From these characteristics, it is not difficult to determine the power system in which the disturbance occurred, J3 of this power system must be regulated accordingly by active power. The stations of this system must accept the power of the resulting deficit. In this case, the principle of selectivity of power control is observed. Stations of neighboring power systems in the steady state should not change their power. In order to maintain the stability of intersystem power transmission lines at the first stage of the transition process after the formation of a deficit (excess) of active power, the control over flow deviation and its derivatives should be made in all power systems. But integrators in power flow control systems should be turned on only in the power system where there is a shortage (excess) power. If this condition is observed, the selectivity of regulation is observed. Ultimately, all the power of the unbalance should be taken to the power grid stations in which this unbalance arose. Diagram of the device for implementing this method. 2) includes in pins 1 of the considered power system, buses 2 of the neighboring power system, tires 3 of the second neighboring power system, intersystem electricity transmissions 4, 5, power flow accumulator 6, sensor 7 deviation of power balance balances from this value, proportional link 8 of the flow regulator, differentiator link 9 of the flow regulator, integrating link 10 of the power flow controller, adder 11, actuator 12 of the flow regulator, equivalent to turbine 13 and equivalent generator 14 of the power system, voltage frequency sensor 15 on power system tires, differentiator 16, device 17 for comparing the signs of the sigdf of the derivative of the frequency -t- and from the dt clones of the balance of flows of LRr, logic element 18. The scheme works as follows When an unbalance of active power occurs in the power combination at the output of the sensor 7 of the deviation of fats to flows from of a given value .j, a signal appears that is proportional to the difference between the ARPS RPS and the value P, (is equal to the sum of all flows over external communications of the power system. When the balance drops from a given value, the work begins at regulator flow. Proportional-differential regulation is carried out in any case, regardless of the power system in which the disturbance occurred. Signals proportional to the magnitude of the DR and the derivative of D.RG, |; , come from links 8 and 9 to the adder 11, which by its output is connected to the input of the executive body 12 of the flow regulator. Depending on the sign, the power of the energy regulating units increases or decreases.

system.

The integrator link 10 of the flow regulator is put into operation if an unbalance has arisen in this power system. The scheme provides a comparison55

df

lr.

and -: -, which

ps dt

Claims (1)

device 17. With proportional and integral components, with control detuning with unbalance of power in adjacent power systems, the sediments on the power system tires are equivalent to the fact that, in order to increase the reliability and economy of the 15th signal, the frequency proportional to the voltage on the tires power system, is fed to the input differential, „df cyator 1o. The signal about the value is fed to the input of the device 17 by comparing the signs of the two quantities i- and & P dt f When the characters from the device 17 coincide, the input signal of the logic element 18 receives a inhibitory signal. In this case, the signal at the output of element 18 is equal to zero. If the signs of the indicated quantities do not coincide, the permitting signal at the input of the element 18po is received and a signal proportional to the value of ip is received at the input of the integrating element. A signal proportional to the integral of the magnitude of & RG is sent to the input of the adder from link 10. In this case, proportional-integral-differential regulation of the power flow is carried out. In the steady state, the entire primary power imbalance is controlled by the stations of the power system. Neighboring power systems, having similar power flow regulators, are involved in the regulation of power flow, but only in the first stage of the process. If the selectivity is observed, the initially gained (reduced) power in the steady state is reduced to the initial level. Claims The method of regulating power flows in the integrated power system, according to which the power flow balance of each power system is measured, compared with a predetermined value, generates a control signal to control power plants as a function of defining power flow balance. including at least the incorporated power system of the joint operation of the grid by increasing the selectivity of controlling the power flows in the power systems, the detuning of the control effect in case of unbalance of power in the adjacent power systems is carried out by fixing the signs of the deviation signals the balance of power flows of each power system with a given value and the frequency derivative on the buses of each power system and the elimination of the integral component of the control action in the event of a coincidence of fixed signs of signals.