SU1598041A1 - Method of controlling asynchronized dynamoelectric frequency converter - Google Patents

Abstract

The invention relates to electrical engineering. The purpose of the invention is to increase reliability. The excitation regulator of one machine determines the voltage regulation on its own tires and maintaining the frequency of rotation of the shaft of the asynchronized electromechanical frequency converter, equal, for example, to the average frequency of the connected power systems. The regulator of the excitation of the other machine determines the voltage regulation on its own tires and the regulation of the active power. When one of the sections of the transmission line is disconnected, the power from the side of one machine will become not equal to the established value. Simultaneously, a frequency deviation from the steady state will occur. The frequency control signal is modulated by a modulus signal of the difference between the current active power value and its steady value. This leads to the emergence of an auto-oscillation mode in which the converter operates at a cantilever load. During long-term operation of the converter in this mode, it is shunted and put into reactive power compensator mode. In the case of the restoration of the electric connection, the restoration of the connection is fixed upon the fact of the restoration of the ability to regulate the active power and, accordingly, restore the electric connection with the powerful power grid. 3 il.

Description

central machines (ACM) 3 and 4. connected by a common shaft 5. The AFM is connected via transformers 6 and 7 of the communication and switches 8 and 9 to the power line. A shunt switch 10 serves as a shunt switch for shunting the EMPCH. An angle measuring machine 11 is located on the same shaft with the AFM. The EMPCH mode is controlled by regulators 12 and 13. The outputs of which are connected to the control inputs of the frequency converters 14 and 15 with direct coupling (FC NA). The power supply of the PHCNS is carried out from the secondary windings of transformers 16 and 17, the primary voltages of which are connected to the astator circuit. The control unit of the EMPCH AC contains sensors 18 and 19 of the reference voltage, connected to the transformers 20 and 21 of the voltage of the connected power systems, sensors 22 and 23 of the synchronous projections of the rotor current, sensors 24 and 25 of the voltage, sensors 26 and 27 of the frequencies of the connected power systems, sensors 28 and 29 of active power AFM, sensor 30 of the angular position of the shaft, sensor 31 of the frequency of rotation of the shaft. The primary information is measured using transformers 32 and 33 of the transmission current, transformers 34 and 35 of the AFM voltage, and transformers 36 and 37 of the AFM current. Voltage sensors 24 and 25 are respectively connected to voltage transformers 20 and 21, active power sensors 28 and 29 are connected to current transformers 32 and 33 and voltage transformers 20 and 21, respectively, frequency sensors 26 and 27 are respectively connected to transformers 20 and 21 power system voltages, a shaft speed sensor 31 and a shaft angular position sensor 30 are connected to a measuring machine 11.

The excitation controllers 12 and 13 consist of converters 38 and 39 coordinates, adders 40-43, proportional to differential-integral (PID) converters 44-47; The voltage settings are set by potentiometers 48 and 49. The active power P is set by a potentiometer 50. The inputs of the PID converter 47 receive signals from blocks 51 and 52 of the control signal conditioners (BFSU), whose inputs are connected to the corresponding frequency sensors 26 and 27 and sensors 28 and 29 active power. The output signals of the BPSU 51 and 52 are input signals of the control unit 53, which switches the keys 54-57, turns on the automatic synchronizer 58 and switches the input signals of the BFSU 51 and 52.

The BFSU 51 or 52 consists (Fig. 3) of the formers 59 and 60 of the established values of the active power and frequency, the comparison elements 61 and 62, the keys 63-66, the relay element 67 with the hysteresis advance loop, the modifier 68, the multiplier 69.

A device that implements the proposed control method works as follows.

In normal operation, i.e. When electrical communication exists between the EMPCH AC and the power systems, the excitation controller 12 of the AFM 3 adjusts the voltage on its own buses and maintains the frequency of rotation of the AC EMPCH shaft, for example, equal to the average frequency of the interconnected power systems. The excitation regulator 13 of the other AFM 4 performs 0 regulation of the voltage on its own tires and regulation of the active power, the setting for which is set by potentiometer 50. The keys 54, 57, 63 and 65 are closed, and the keys 55, 56, 64 and 66 I will open 5 you. At the output of BFSU 51 and 52, the signal is zero. When one of the power transmission lines is disconnected, for example, from the side of the AFM 4, the power of the AFM 4 becomes not equal to the steady-state value, therefore at the output 30 of the BFSU 52 adder there will be a constant signal. At the same time, the frequency deviates from the steady-state value, which leads to the operation of the relay element 67 with a leading hysteresis loop. The output signal of the relay element 67 is modulated by the modulus signal of the difference between the current value of the active power and its steady value. The modulation is carried out by a multiplier 69 40 and a modulator 68. This control leads to the emergence of a self-oscillation mode, the presence of which is fixed by the control unit 53. The presence of self-oscillating mode 45 indicates that the AC EMPCH is operating at a cantilever load. At the same time, the control unit 53 switches the control of the EMPCH control system to the law that ensures maintaining the equality of the current values of the frequencies of the connected power systems. This operation is performed by turning off the keys 54 and 57 while simultaneously turning on the keys 55 and 56. During long-term operation of the EMPCH AC in the console mode, the control unit 5553 enables the automatic synchronizer 58, which bypasses the EMPCH AC by turning on the switch 10. Upon switching on the switch 10 the control unit 53 switches the EMPS to the reactive power compensator mode by turning on the key 54 and turning off the keys 55-57.

However, this sequence of operations may be disrupted in case of restoration of electrical communication, for example, with successful reclosure. To fix the fact of the restoration of the electrical communication simultaneously with switching to the law ensuring the equality of the current values of the frequencies of the connected power systems, the input signals in the BFSU 52 are switched, the keys 63 and 65 are turned off, the keys 64 and 66 are turned on. the fact that the ability to regulate active power is restored. The ability to regulate active power is confirmed by the following operations; using the element 61, the comparison of the installed and current values of the active power of the machine feeding the cantilever load, when this difference goes beyond the specified limits, generates a control signal that provides an approximation (active power to the steady state, when active power is restored) control signal relay element 67 with advanced hysteresis loop), and this control signal is modulated (multiplier 69) by the value (element 68) of the difference between the current and the set values of Stots, when given repeatedly; The number of outputs of the difference of active Capacities beyond the permissible limits within the time specified fixes the fact that the ability to regulate active power and, accordingly, the restoration of electrical communication with a powerful power system is restored. The control unit 53 switches the keys 54-57 and 63-66 to the position corresponding to the normal operation of the EMPS.

In emergency situations leading to. and, changing the frequencies in the associated systems, the EMPCH speaker retains the ability to regulate the active power, therefore, although the output of the relay element 67 will be a signal, the output of the multiplier 69 will be a zero signal. Additional verification of the restoration of communication allows a transition to the pre-emergency control law. These technical measures increase the selectivity and therefore increase the reliability of the AU

EMPCH In the case of long-term operation of the AC EMPCH, the unit is shunted by a switch 10 to the cantilever load, permission to turn on which comes from the auto-synchronizer 58.

Thus, the proposed invention enhances the reliability of the operation of the APS of the EMPCH in the console mode and in the restoration of communication between the APS of the APS and the power system.

Claims (1)

Claims of Invention The method of controlling an asynchronized electromechanical frequency converter (AC EMPCH) according to aut. St. No. 1354334, characterized in that, in order to increase the reliability of the EMPCH AC, the active power of the second AC ACP machine is additionally measured, the ramp values of the active powers of the AC EMPH machine are recorded, the generated control signal approximating the current frequency values to the established values before serving at the machine controlled by active power is multiplied by the value of the recorded surge of the active power of the AC EMPCH machine, from which the frequency difference has gone beyond the specified limits, and when the AC EMPCH is operating according to the control law, ensuring that the current values of the connected power systems are equal, overload of the active power of the machine supplying cantilever load, when this overshoot goes beyond the specified limits, form a constant-magnitude signal with a sign ensuring the reduction of this power surge, multiply it by the difference between the current and the set frequency values from the side of the machine supplying the cantilever load, the resulting additional signal is summed up with the signal generated according to the law ensuring the equality of the current frequencies of the connected power systems while decreasing this scribe below the specified limits remove the additional signal and Repeatedly set the number of outputs of this set for specified limits for a specified time record the restoration of the electrical connection with the power supply. system and transition to the formation of control signals of EMPCH AC in the normal mode. power system / Qy r-ayD neither Energ, osastema2 9us.2 otgar OmZlu)