SU1427478A1 - Arrangement for coupling two power systems - Google Patents

Abstract

The invention relates to electrical engineering. The purpose of the invention is to improve the reliability of power supply to consumers during a long-term increase in the frequency difference of the interconnected power systems. The device contains two electromechanical frequency converters, each of which includes an asynchronized synchronous machine 1 (9) and a synchronous machine 2 (U). When the difference between the frequencies of the combined power systems is below the limit value, the specified converters are connected in parallel; When Energostenen reaches S, oz, and the frequency difference of the limiting value, the actuating element of the block 14 of the excitation voltage of the machine 9 is triggered. With a further increase in the slip between the frequencies of the combined power systems, the reserve on the amplitude value of the excitation voltage of the asynchronized machines will be exhausted. The signal from the output of the slip block 24 will exceed the signal proportional to the limit value of the slip Dcr. The threshold element 25 and the relay element 26 are actuated. The synchronized synchronized machine is switched to the deep under-excitation mode, which leads to the machine being overloaded by the stator and rotor currents. When the overload times are exceeded, the switches 17 and 19 are turned off and the switch 18 is turned on. The electromechanical frequency converters are switched from parallel to serial. With a serial connection, it is possible to allow a long-term operation of the device with an increased in comparison with the calculated slip value between the frequencies of the power systems. 5 il. ou fzsH O) i4iik 1C 4: H 00

Description

The invention relates: to w.sche) about aFiepreTHKf, namely to devices for combining power supply systems of non-temporary current,

The purpose of the invention is to reduce the reliability of electricity supply by consumers with a long-term increased difference between the chips of the integrated power systems .10

FIG. 1 shows a diagram of the device being predicated; in fig. 2, 3 - fragments of the block diagram of the control of the device switches according to the operational parameters of a single electric-15 converter; Figures 4, 5 are fragments of structural diagrams of the regulators of asynchronized synchronous machines.

The device consists of the first 20 electromechanical frequency converter, made in the form of an asynchronous synchronous machine (LPC) 1, a synchronous machine (cm) 2, a frequency converter 3 (FC), excitation system 25 AFM 1, transformer D PC power supply 3, controller 5 AFM 1, block 6 of the excitation voltage level of the AFM 1, the sensor 7 of the angular position and rotor speed of the machines of the first 30 electromechanical converter and the sensor 8 of the voltage vector of the power system I, the second electromechanical frequency converter containing the AFM 9, CM 10, IF 1, transformer 5 power supply converter 12, 11, AFM regulator 9 9, AFM excitation voltage level unit 14, sensor 15 of the angular position and rotation speed of the rotor of the second electromechanical converter 40 and vector sensor 16 power supply system II, switches 17-19, rotor current sensor 20 and stator current sensor ACM 9, rotor current sensor 22 and tokad5 sensor 23 of the stator AFM 1, slip unit 24, threshold element 25, relay elements 26 and 27, relay 28 and 29 times, logical circuit OR 30, closing contacts 31 of the executive cQ m This unit 14, the closing contacts 32 of the relay element 26, the closing contacts 33-36 and the opening contacts 37 of the relay element 27, the sum torus 38, the sensor 39 and the active power control sensor 40 of the AFM 9 and channel 9 of the active power control AFM 1 and 9 Kangglu 42 controls the speed of rotation of the shaft of the AFM 9, the sensor 43 and the setpoint 44 of the active power of the AFM 1, the sensors 45 and 46 of the frequency of the power systems T and 11.

The stator windings of the ACM 1 are connected to the power supply (system I, and the stator windings of the ACM 9 are connected to the power system of the TT. The stator windings of the CM 2 are connected via a normally closed switch 17 to the power system of the TT, and the stator windings of the CM 10 are connected to the power system I. The windings The rotor of the AFM 1 supplies the excitation voltage of the required frequency and amplitude from the inverter 3, which is controlled from the controller 5. The output of the angular position and rotation speed sensor 7 of the common shaft of the AFM 1 and CM 2 machines and the output of the voltage sensor 8, the sensor outputs 43 and the active power sensor 44 are connected to the inputs of the regulator 5. The input of the field voltage level 6 unit is connected to the excitation windings of the AFM I. The excitation voltage from the inverter 1I is supplied to the windings of the AFM. The voltage is supplied from the transformer 12 connected to the power system of the TT. The control of the operation of the inverter 1 1 is implemented with the help of the regulator 13. The input of the block 14 of the level of the excitation voltage is connected to the excitation winding of the AFM 9. The outputs of the sensors 15, 16 and 40, the setpoint 39 of the active power and the arithmetic unit 38 are connected to odes regulator 13.

The control systems of CM 2 and CM 10 are not shown. The stator windings CM 2 and ACM 10 are connected via a closing switch 18. The inputs of the slip block 24 are connected to the measurement voltages of the connected power systems I and IT. Series-connected relay element 26 and threshold element 25 are connected to the output of block 24. A signal proportional to the allowable frequency difference of the connected power systems I and TT (EPR) is applied to the second input of the threshold element 25 according to the condition of operation of the converters.

The outputs of the sensors 20 and 21 current (Fig. 2 and 3) are connected to the inputs of the relay 28 and 29 with a time-dependent, time-dependent. Through the closing contacts of the relay 28 and 29, connected according to the OR scheme, and the series-connected closing contacts 31 and 32, a signal is supplied to the relay element 27. The contacts 28 and 29 and 30 of the relay

Element 27 signals the control units of the switches 17-19.

To the input of the channel 4 for controlling the active power of the AFM 9 of the regulator 13 (FIG. 4), the outputs of the sensor 40 and the active power setting device 39 are connected via the disconnecting contacts 37 of the relay element 27. The adder 38 and the sensor 15 are connected via the closing contacts 36 of the relay element 27 to the channel input 42 controls the speed of rotation of the shaft of the second converter machine. The inputs from the sensor 40 provide signals from current sensors and stator voltage ACM 9.

The inputs of the active power control channel 41 of the AFM 1 of the regulator 5 (FIG. 5) are connected to the outputs of the sensor 43 and the active power setpoint 44. The signals from the current and stator voltage sensors AFM 1 are supplied to the inputs of the sensor 40,

The device works as follows.

Until the difference between the frequencies of the combined power systems has reached the limit value (for example, 1.5 Hz) and the excitation voltage of the rotor, the AFM 1 and the AFM 9 have not reached their ceiling values, the device operates in the nominal mode when the connection between the power systems I and II is through two electromechanical converters operating in parallel. The angular velocity of rotation of the shaft and / of the converter is determined by the angular velocity of the stator and / synchronous machine voltage vector (e.g., for the second converter l.e For the first. The values 1 and 2 are the angular velocities of the voltage vectors of the power systems I and II. Angle The speed of the voltage vector in the rotor uJf is formed by a frequency converter controlled by the AFM controller as the difference between the frequencies of the electrical system and the frequency of rotation of the rotor:

for AFM 1 ,, for AFM 2 Chl), (1)

To generate control signals for the frequency of the output voltage of the converters, the regulator 5 receives signals from sensors 7 and 8, and the regulator 13 - from sensors 15 and 16. Thus, a steady state frequency of electromechanical converters is provided. Control u; j,

l converters, can provide voltage regulation or reactive power, frequency difference

connected power systems or power flow between them. Supply, for example, to the input of the channel 41 of the regulator 13 (FIG. 4) signals from the sensor 39 about the actual value of the active

AFM 9 and the signal from the setting unit 40 for the required amount of active power through the closed contact 37 - in normal mode, the controller 13 via channel 41, provides support

given power flow through the second converter. If the input of the channel 41 of the regulator 5 to apply a joint signal from the sensor 43 and the setting device 44 (FIG. 5), then this will allow

controllers 5 and 13 control the flow. power between the connected power systems I and II in accordance with the selected tasks of the active power setters 39 and 44. Thus,

in normal mode, with the parallel operation of both electromechanical frequency converters, the AFM 1 and the AFM 9 are controlled by the active power of the machines, which

ensures the maintenance of the specified power flow through the converters, and, consequently, between the interconnected power systems. In addition, the AFM, like the CM, can perform, for example, control by voltage level at the outputs of the machines.

To ensure stable and reliable operation of the converters in the steady state, it is necessary to fulfill the conditions

() ;;), - (2)

where is the limit value of the slip of the rotor of the AFM, determined by the design and operating parameters of the machine.

When the difference between the frequencies of the combined power systems reaches the maximum permissible value, when the COD- - (l 4np excitation voltage AFM

(e.g., the AFM 9) increases to its ceiling value, which causes the actuator of the unit 14 to operate and the contacts 31 to close. With a further increase

the slip between the frequencies of the energy-connected reserve by the amplitude value of the excitation voltage of the asynchronized synchronous machines will be exhausted. So, how is the signal from you51427478

block 24 exceeds the signal proportional to i) j ,, p arriving at the second input of threshold element 25, then relay element 26 triggers and closes its contacts 32 in control circuit 1 of relay element 27. To provide the specified active power flow through the device to energy correction signals This allows the power to be supplied to the deficient power system with a long decrease in the frequency (for example, up to 47–48 Hz) of a power equal to the nominal electromechanical frequency converter, instead of losing the connection with the power system when the condition (2) | o by unification is not met, the AFM is switched to the deep allowable current overload of the AFM after the time elapses. under-excitation with significant consumption of reactive power. When this occurs, the stator and rotor windings are overloaded with current. The inputs 15 of the relay 28 and 29 of time receive signals that are proportional to the overload values of the stator and the rotor of the AFM 9, which leads to their start-up in accordance with the characteristics of triggering gehani. If the permissible time of the stator or rotor AFM is increased by a current of 28 and 29, the contacts 31 and 32 will send the control signal 25 to the contacts of the relay element 27 with their contacts. control signals are given To turn off the switches 17 and 19 and turn on the synchronization of the switch 18 subject to the conditions 30. By switching the circuit of the device, the operating mode of the electromechanical frequency converters changes from parallel to series 5 It’s possible to allow the device to work for a long time in the mode of flexible communication with doubling versus the calculated slip value between the frequencies

Claims (1)

Invention Formula A device for connecting two power systems, containing an electromechanical frequency converter, made in the form of two AC machines with rigidly connected shafts, the stator windings of which are connected to the power system, at least one of the machines being asynchronized synchronous, controlled frequency converter for supplying excitation windings, regulator with control channels for active power and shaft rotation speed, excitation voltage level unit connected to the input of the motor excitement of the asynchronized mayine, the actuator of the excitation voltage level unit with closing contacts, the sensor of the angular position and the rotor rotation speed, the serially connected regulator and controlled frequency converter are connected to the input windings of the asynchronized synchronous machine of the frequency sensors on the buses correlation of signals from the active power flow master It allows you to transfer to a deficient power system with a long decrease, frequencies (e.g., up to 47-48 Hz) power equal to the nominal electromechanical frequency converter, instead of losing the connection with the power connection after the time of the permissible overcurrent of the AFM. by unification after the time of permissible overcurrent on the AFM. Invention Formula A device for connecting two power systems containing an electromechanical frequency converter, made in the form of two AC machines with rigidly connected shafts, the stator windings of which are connected to the connected power systems with at least one of the machines being asynchronized synchronous, controlled frequency converter for supplying the excitation windings, a regulator with control channels for active power and speed of rotation of the shaft, a block of voltage level of the excitation connected to the input of the washing approx excitation Ma'in asynchronized, the actuator voltage level of the driving unit to make contact, and the angular position sensor of the rotor rotational speed, wherein the controller serially connected and controlled by a frequency converter connected to an input of excitation windings asynchronized us synchronous wave frequency and tire sensors on communication zy power systems. By changing the scheme of the connected power systems and the slide-blocking unit of the converters, the control contacts of the relay element 27 can make the necessary changes in the control laws of the regulators 5 and 13. For example, opening the contacts 37, 45 disable the control channel of the active power-ACY 9 and make contacts 36 to the input of the shaft speed control channel 42 to send signals from the sensor 15 and the adder 38, gg at the input of which there is a signal equal to 0.5 (OT + u) j), thereby the AFM 9 is switched from the power flow control mode to dir m control rotation speed of the rotor shaft gg second transducer. The control law — the AFM 1 of the first converter can remain unchanged with the necessary one in such cases. In order to improve the reliability of the power supply to consumers during long-term difference between the frequencies of the interconnected power systems, it is equipped with a second electromechanical-1 frequency converter, three switches with control units, current sensors of the stator and rotor of asynchronized synchronous machines, a threshold element, two sensors and control devices for the flow of active power through electromechanical transducers, an adder, two relay elements and a time relay, one The switch is connected to the stator windings of the inverter masks, which are connected to different power systems through switches. power systems and the block In order to improve the reliability of the power supply to consumers during long-term difference between the frequencies of the interconnected power systems, it is equipped with a second electromechanical-1 frequency converter, three switches with control units, current sensors of the stator and rotor of asynchronized synchronous machines, a threshold element, two sensors and control devices for the flow of active power through electromechanical transducers, an adder, two relay elements and a time relay, one The switch is connected to the stator windings of the inverter masks, which are connected to different power systems through switches. and time sensors GJ-p p jjie are connected to the input of the additionally introduced logical OR circuit, the output of which is connected to the input of the second relay element through the sequentially connected actuator contacts of the actuating element of the block of the voltage level of the primary voltage and the first relay element to the second relay element which are connected to the control units of the switches, the outputs of the frequency sensors are connected to the inputs of the adder and the slip block, to the input of which are connected in series the connected threshold element The ent and first relay - Hbrii element of the slip block, to the input FIG. 2 F Phie. the active power control channel of one of the regulators is connected to the sensor and the flow master of active power through a corresponding electromechanical frequency converter, the second master and flow sensor of the active power are connected via the disconnecting contact of the second relay element to the input of the active power control channel of the other regulator, to the speed control channel input rotation of the shaft which through the fourth closing contact of the second relay element is connected to the angular position sensor and soon rotation no rotor and adder. Off 17 Rel. J9 On 1B Fig.Z b-r {wb Thebes. five