JP2703441B2 - Operation control device for wound induction generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exciting means for exciting a secondary winding of a wound induction generator, comprising an inverter, a converter,
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control device for a wound-type induction generator comprising a chopper and a DC capacitor, and more particularly to an operation control device for a wound-type induction generator capable of reliably protecting an exciting means in the event of a power transmission system accident. It is.

[0002]

2. Description of the Related Art In recent years, in hydroelectric power generation, there has been a growing need for a so-called variable speed power generation system which operates at a rotational speed at which the hydraulic efficiency of a turbine becomes maximum with respect to a change in head and a change in load. Hereinafter, one example of the variable speed power generation will be described.

FIG. 7 shows a variable speed power generation system using a conventional cycloconverter (Bundesminist, West Germany).
erium fuel Forschung und
Technologie's research papers BMFT-FB-
FIG. 69 is a block diagram illustrating a configuration example of T84-154 (1), paragraph 96, by the method disclosed in FIG. 3.2.11). In the system shown in FIG. 7, the secondary current of the wound induction generator is controlled by a frequency converter such as a cycloconverter, and the frequency on the primary side is controlled to be constant irrespective of a change in rotation speed. This is a variable speed power generation system of the excitation system. This system is characterized in that the capacity of the converter can be reduced, and therefore, it is particularly applied to a large-capacity power plant.

Referring to FIG. 7, a wound induction generator (IM)
The primary winding 700 is connected to a transmission line 701, and the secondary winding is connected to a frequency converter 702 composed of a cycloconverter, so that secondary current control is performed. That is, the three-phase command values i _r1s , i _r2s , and i _r3s of the secondary current are given to the frequency converter 702, and are compared with the detection value i _{rd of the} secondary current, and the detection value always matches the command value. The control is performed as follows. The primary current has a current component I _{sq in} phase with the primary voltage U _s1 and a current component I
_sd and detected, and the magnitude of the primary voltage Us | Us |
The primary active power P _sd and the primary reactive power Q _sd are detected by the product of

On the other hand, a command value P _ss of the active power and a command value Q _{ss of the} reactive power are given, and the detected values P _sd and Q _{sd are} respectively provided.
The secondary current is controlled via the active power regulator PR and the reactive power regulator QR and the frequency converter 702 such that the deviation becomes zero.

The method of generating power by secondary excitation by a cycloconverter has the following properties.
That is, the cycloconverter generates large reactive power on the AC input power supply side, and this reactive power must be supplied from the primary side of the generator IM, so that the capacity of the generator increases. Further, in a system using a cycloconverter, a harmonic current on the AC input power supply side is large, and voltage distortion due to the harmonic current occurs, so that high-quality power generation cannot be performed. Furthermore, the power plant is operated in parallel with the power transmission system.However, if a short circuit accident or the like occurs on the power transmission line due to lightning damage, a negative-phase component is put on the power transmission line, and the cycloconverter becomes inoperable and stops, A high voltage caused by the negative phase component is induced on the secondary side, and this high voltage is applied to the thyristor element constituting the cycloconverter, which may cause a voltage breakdown of the thyristor.

[0007] The variable-speed power generation system using the cycloconverter shown in FIG. 7 has the above-mentioned properties. Therefore, when operating in parallel with the power transmission system, the system should be operated with careful consideration of these restrictions. There must be. For this reason, there is a need for the appearance of excitation means for secondary excitation of a wound-type induction generator capable of reducing voltage distortion, reducing the capacity of the wound-type induction generator, and operating stably even in the event of a transmission system failure. I have.

[0008]

As described above, in a system in which the secondary side of a wound induction generator is excited by a conventional cycloconverter to generate electric power, the capacity of the generator is increased and voltage distortion is reduced. There is a problem that it is relatively large and no measures are taken in case of a transmission line system accident, so that high-quality power cannot be supplied stably when operating in parallel with the transmission system.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the capacity of a generator, to reduce voltage distortion during power generation, and to stably protect an exciting means even in the event of an abnormality such as a transmission line system accident. It is an object of the present invention to provide an extremely reliable operation control device for a wound induction generator capable of supplying high-quality electric power to a transmission system.

[0010]

According to the present invention, a primary winding of a wound-type induction generator having a primary winding and a secondary winding is connected to a transmission system via a transformer. In a device that controls the operation of a wound induction generator that generates power by exciting its secondary winding by exciting means and supplies power to the power transmission system, the secondary winding of the winding induction generator An inverter connected to receive power supply from the DC bus to convert DC power into AC power and supply it to the secondary winding, a converter that converts AC power to DC power and supplies DC power to the DC bus, A DC capacitor installed on the bus, a chopper installed on the DC bus, and a control device that controls the converter and, if necessary, the inverter to suppress an increase in the DC bus voltage when an accident in the transmission system is detected. If, upon detecting an abnormal rise in the voltage of the DC bus, and configured by a chopper control means for controlling the chopper so as to suppress the increase of the DC voltage.

[0011]

In the operation control device for a wound induction generator according to the present invention, when power generation is performed in a steady state, the converter is controlled so as to keep the voltage of the DC bus constant, so that the converter has a winding induction motor. Only the active power induced on the secondary side of the generator flows to the AC line side. As a result, the primary winding of the wound induction generator does not need to supply reactive power, which was required in the conventional cycloconverter method, in the method using the converter. As a result, the capacity of the wound induction generator is reduced. Can be reduced as compared with the cycloconverter system. Further, since the converter is normally operated by the PWM control method, the current flowing through the AC line contains almost no harmonic components, and as a result, the voltage distortion of the generated voltage can be remarkably reduced.

On the other hand, when an accident occurs in the power transmission system or the like, control is performed so as to prevent the voltage of the DC bus from rising by a normal gate signal to the converter. Also,
If the primary voltage of the generator at the time of the transmission system accident is smaller than the predetermined value, the DC voltage maintenance function of the converter is lost to stop the normal gate signal of the converter, and the DC voltage tries to rise, In this case, as the second stage, the chopper is turned on / off to control so as to suppress an increase in the DC voltage. Further, when the DC voltage is about to rise further despite the suppression of the DC voltage rise by the chopper, as a third step, the switching elements constituting the inverter are controlled so as to be simultaneously turned on. The secondary winding of the machine is short-circuited through the elements constituting the inverter, so that the current of the secondary winding does not flow into the DC capacitor, and the DC voltage can be prevented from rising.

As described above, when a high voltage due to an increase in the DC bus voltage is applied to the excitation means for secondary excitation of the wound induction generator in a power transmission system accident or the like, the DC voltage control by the converter can be performed. Since the chopper control and the short-circuit mode control of the inverter work in combination to reliably prevent an abnormal rise in the DC voltage, it is possible to reliably protect the excitation means in the event of an abnormality such as a transmission system accident. It operates stably both in a steady state and during a transient event of a transmission line accident, and can supply highly reliable and high-quality power to the transmission system. In other words, the reliability when the variable speed power generation system is operated in parallel with the system can be improved.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail.

FIG. 1 is a diagram showing an example of the overall configuration of an operation control device for a wound induction generator according to the present invention. In FIG. 1, reference numerals 1, 2, 3, and 4 denote transmission lines in which inductance, resistance, and stray capacitance are distributed. Reference numeral 5 denotes a power system that is further connected to the transmission lines 1, 2, 3, and 4, 6, 7, 8, and 9. Indicates that the transmission line in the accident section was disconnected at the time of the transmission line accident, and transmission lines 1, 2, 3, 4
Is a circuit breaker that protects The power plant 10
Is constructed by connecting a primary winding of a wound induction generator 12 to a power transmission system 13 via a main transformer 11.

On the other hand, the operation control device is basically connected to the secondary winding of the wound induction generator 12 and
P and 13N, which are supplied to an inverter 14 that converts DC power into AC power and supplies an exciting current to a secondary winding of the wound induction generator 12 and DC buses 13P and 13N of the inverter 14, respectively. A chopper circuit 15 composed of a resistor 151 and a switching element 152, a DC capacitor 16 provided on the DC buses 13P and 13N, and a power from a primary winding of the wound induction generator 12 via a transformer 17. A converter 1 that receives supply, converts AC power into DC power, and supplies DC power to DC buses 13P and 13N.
It consists of eight.

Further, in this embodiment, the following elements are added. That is, 19U, 19V, 19W
Is a secondary current detector for detecting the secondary current of the wound induction generator 12, 20 is a DC voltage detector for detecting the voltage of the DC buses 13P and 13N and outputting a DC voltage detection signal _Edf , 21
U, 21V and 21W are converter current detectors for detecting the current of the converter 18.

Reference numeral 22 denotes a voltage detecting transformer for insulating the primary voltage of the wound induction generator 12 and leading it to the control circuit. Reference numeral 30 denotes a voltage for detecting the primary voltage phase Θ ₁ of the wound induction generator 12. Phase detector, 31 is a winding type induction generator 12
Rotor phase detection circuit for detecting the rotor phase Θ _r
2 is a calculator for calculating from the primary voltage phase theta ₁ and rotor phase theta _r, secondary voltage phase theta ₂ of the wound-rotor induction generator 12.

On the other hand, 40 introduces the primary winding voltage of the wound induction generator 12 through the voltage detecting transformer 22 and monitors the change of the primary winding voltage at the time of an accident of a transmission line or the like, and FIG. 2 is a first accident detector for outputting a first accident signal 40S, the details of which are shown in FIG. That is, in FIG. 2, reference numeral 41 denotes an arithmetic unit which introduces a primary voltage of a three-phase alternating current of the wound induction generator 12 and outputs a primary voltage signal E _1s ′ represented as an amplitude value of a combined vector. _{Reference numeral} 42 denotes a filter, which removes the AC component to a required level and outputs it as a first primary voltage signal E _1s when the primary voltage signal E _1s ′ includes an AC component. 43 is a setting device,
Set the first setting level V _1s ^* . A comparator 44 compares the first primary voltage signal E _1s with the first set level V _1s ^*, and outputs a first fault signal 40S when the signal E _1s becomes smaller than the signal V _1s ^*. . The first fault signal 40S acts on a converter control logic described later, and is used to determine whether or not to operate the converter 18 at the time of a fault.

Reference numeral 50 denotes the primary winding voltage of the wound induction generator 12, which is introduced through the voltage detecting transformer 22, monitors the change in the primary winding voltage at the time of an accident of a transmission line or the like, and FIG. 3 shows a second accident detector that outputs a second accident signal 50S. That is, in FIG. 3, an arithmetic unit 51 introduces a three-phase AC primary voltage of the wound induction generator 12 and outputs a second primary voltage signal E _2s represented as an amplitude value of a combined vector. 52
Is a setting unit for setting a second setting level V _2s ^* . 5
A comparator 3 compares the second primary voltage signal E _2s with the second set level V _2s ^*, and outputs a second fault signal 50S when the signal E _2s becomes smaller than the signal V _2s ^*. . The second fault signal 50S acts on an inverter control logic, which will be described later, and is used to determine whether or not to operate the inverter 14 at the time of a fault.

Here, how the first accident detector 40 operates when an accident due to lightning damage or the like occurs in the power transmission system will be described with reference to FIG. That is, the transmission line 3 of FIG.
In case of lightning damage in A etc., most of the accidents are caused by ground faults in all three-phase transmission lines (three-phase ground fault: 3LG)
Alternatively, one of the three-phase transmission lines has a ground fault (one-phase ground fault: 1 L).
G) It is an accident. FIG. 2A shows signal waveforms at various points when a three-phase ground fault occurs in a transmission line.
Voltage after the accident reduced primary voltage signals E _1s' sharply for between three phases are short-circuited, all the three-phase ground fault in the transmission line occurs at time t ₁ is detected by a small value. FIG. 2B shows signal waveforms at various points when a one-phase ground fault occurs in the transmission line. In a single-phase ground fault, the voltage of the phase that survived the ground fault remains,
Since the voltage is strongly unbalanced, the primary voltage signal E _1s ′ is detected in a form oscillating at twice the transmission line frequency as shown in FIG.
The voltage after the accident is detected with a somewhat large value. The first fault detector 40 shown in FIG. 2 outputs the first fault signal 40S when the first primary voltage signal E _1s is extremely reduced as shown in the figure due to a serious fault such as a three-phase ground fault. On the other hand, in the case where the first primary voltage signal E _1s is detected to be somewhat large as shown in the figure in a light accident such as a one-phase ground fault accident, the first accident signal 40S is not generated so that the first accident signal 40S is not generated. Setting level V _1s
^* Is set.

The operation of the second accident detector 50 when an accident such as lightning damage occurs in the power transmission system will be described with reference to FIG. FIG. 3A shows signal waveforms at various points when a three-phase ground fault occurs in a transmission line. Voltage after the second primary voltage signal E _2s for three-phase ground fault in the transmission line is short-circuited all between the generated three-phase decreases drastically accident time t ₁ is detected by a small value. FIG. 3B shows signal waveforms at various points when a one-phase ground fault occurs in the transmission line. In the case of a single-phase ground fault, the voltage of the phase that has passed through the ground fault remains, but since the voltage becomes strongly unbalanced, the second primary voltage signal E
_2s is detected in the form of oscillating at twice the transmission line frequency as shown in the figure, and the voltage after the accident is detected with a somewhat large value. In the second fault detector 50 shown in FIG. 3, when the second primary voltage signal E _2s extremely decreases as shown in FIG. In the case where the second primary voltage signal E _2s is detected to be somewhat large as shown in FIG. 2B in a minor accident such as an accident, the second set level is set so as to generate the second accident signal 50S. V _2s ^* is set.

On the other hand, an inverter control circuit 100 controls the inverter 14 so that the inverter 14 supplies a predetermined secondary current to the secondary winding of the wound induction generator 12. A secondary current command value I ₂ ^* to be supplied to the secondary winding is provided. In the inverter control circuit 100, an arithmetic unit 102 converts an AC secondary current of the wound induction generator 12 into a DC secondary current signal _I2f . Reference numeral 103 denotes a computing unit, which is a current command value I
₂ ^* and for detecting the error △ I ₂ of the secondary current signal I _2f. 1
An amplifier 04 amplifies the error ΔI ₂ and amplifies the voltage command V
₂ Outputs ^* . Reference numeral 110 denotes an inverter gate circuit which operates in response to the voltage command V ₂ ^* and the secondary voltage phase Θ ₂ of the wound induction generator 12, and the frequency of the output voltage of the inverter 14 is defined by the secondary voltage phase Θ _2. the control of the switch elements 141U~141Z of the inverter 14 to generate the magnitude is indicated by the voltage command V ₂ ^* voltage signal 11
0U to 110Z are generated.

Reference numeral 120 designates the normal gate control signal to the inverter 14 when receiving the second accident detection signal 50S, and the inverter 1 when receiving the short-circuit mode signal 204S.
4, the switch elements 141U, 141V, 141
W (or switch elements 141X, 141Y, 141)
Z) is an inverter control logic for controlling to simultaneously supply an ON command, and details thereof are shown in FIG. In FIG. 4, 121U to 121Z are AND circuits,
The control signals 110U to 110Z generated from the inverter gate circuit 110 are input to one input, and the second fault detection signal 50S is introduced to the other input, and the second fault signal 50S Occurs, the control signals 110U to 110W act so as not to pass through the AND circuit. Reference numerals 122U to 122W denote OR circuits, which receive the outputs of the AND circuits 121U, 121V, and 121W and the short-circuit mode signal 204S as inputs, and output the short-circuit mode signal 204S.
When the gate signals 100U, 100V, 100
W acts to forcefully output an ON signal.

Here, in the event of a transmission line fault, a second fault signal 50S is generated first in time series, and then a short-circuit mode signal 204S is generated. First, the passage of control signals 110U to 110Z is prohibited by second accident signal 50S, and the inverter stops. Thereafter, when the short-circuit mode signal 204S is generated, the gate signals 100U, 100V, 1
00W, an ON signal is forcibly output and the gate signal 1
Since the OFF signals are output to 00X, 100Y, and 100Z, when the short-circuit mode signal 204S is generated, 141 of the switching elements constituting the inverter 14 is output.
U, 141V, 141W are simultaneously turned on, so that the secondary winding of the wound induction generator 12 is connected to the elements 141U, 1W.
41V, 141W and elements 142U, 142V, 142W
Short-circuited via

In the example of FIG. 4, the OR circuit 122U,
122V, 122W are connected to AND circuits 121U, 121V,
Although it is provided behind 121W, this is
It can also be provided behind 1X, 121Y, 121Z. In this case, simultaneously with the generation of the short-circuit mode signal 204S, an ON signal is forcibly output to the gate signals 100X, 100Y, and 100Z, and the gate signals 100U, 10
An off signal is output at 0 V and 100 W.

On the other hand, a chopper control circuit 200 controls the chopper 15 to turn on and off the chopper 15 in accordance with the voltages of the DC buses 13P and 13N and to suppress an increase in the DC bus voltage. The detected DC voltage detection value _Edf is input. In the chopper control circuit 200, reference numeral 204 denotes a comparator, which includes a first set level V _d1 ^* , a second set level V _d2 ^* , and a third set level V _d3.
^* And the DC voltage detection value _Edf as shown in FIG.
Chopper gate signal 205S, short-circuit mode signal 204S
Occurs. FIG. 5 shows that at time t ₁ , an accident occurred in the transmission line, and the inverter stopped, so that the secondary current of the wound induction generator charged the DC capacitor and increased the voltage,
This describes the operation of the comparator 204 when the chopper operates, where V _d1 ^* , V _d2 ^* , and V _d3 ^* are the first,
The second and third set levels, E _df is the DC voltage detection value, 20
5S represents the movement of the chopper gate signal, and 204S represents the movement of the short-circuit mode signal.

That is, when an accident occurs in the transmission line at time t ₁ and the DC voltage E _df starts to rise, it is detected that the DC voltage E _df reaches the second set level V _d2 ^* at time t ₂ . Then, a chopper signal 205S is generated, and the chopper 15 is turned on. When the chopper 15 is turned on, the DC capacitor 1
The charge of No. 6 is discharged through the chopper 15 and the DC voltage _Edf decreases. DC voltage E _df decreases, the DC voltage E _df at t ₃ will detect from reaching the first set level V _d1 ^* to extinguish the chopper signal 205S, turns off the chopper 15. When the chopper 15 turns off, the DC voltage rises again. As described above, when the current flowing from the secondary winding of the wound induction generator 12 to the DC capacitor 16 is relatively small, the DC voltage E _df is determined by the chopper signal 205S based on the chopper signal 205S.
5, through the ON / OFF process of 5, is maintained between the first and second set levels V _d1 ^* , V _d2 ^* .

A case where the current flowing into the DC capacitor 16 is large and the DC voltage _Edf further rises even when the chopper 15 is turned on, for example, in the case of a heavy power line accident will be described. That is, in FIG. 5, after the chopper 15 is turned on at time t _4, further when the dc voltage _df rises, the DC voltage E _df at time t ₅ that matches the third setting level V _d3 ^* And the short-circuit mode signal 20 is detected.
Generate 4S. When the short-circuit mode signal 204S is generated, the signal is introduced into the inverter control logic 120 of FIG.
U, 141V and 141W are forcibly turned on. As a result, the secondary winding current of the wound induction generator 12 does not flow into the DC capacitor 16, and therefore, the time t _{5 in} FIG.
Thereafter, the DC voltage decreases. Further, at time t ₆ , it is detected that the DC voltage E _df coincides with the first set level V _d1 ^* , the short-circuit mode signal 204S is extinguished, and the switch elements 141U, 141V, 14
When the 1 W on-gate is stopped, the secondary winding current of the wound induction generator 12 again flows into the DC capacitor 16, and the DC voltage rises. As described above, if the current flowing from the secondary winding of the wound induction generator 12 to the DC capacitor 16 is large due to a heavy power line accident or the like and the voltage rises despite the suppression of the DC voltage rise by the chopper 15, the inverter By forcibly turning on the elements that constitute the DC power supply 14, the current flowing into the DC capacitor 16 can be cut off.
_It can be prevented from rising above _d3 ^* .

On the other hand, reference numeral 300 denotes a converter control circuit for controlling converter 18 so that converter 18 maintains the DC voltage of DC buses 13P and 13N at a predetermined value. Value E
_d ^* is given. In the converter control circuit 300, an arithmetic unit 302 detects an error ΔE _d between the DC voltage command value E _d ^* and the DC voltage detection value E _df . 303
It is an amplifier, and outputs the converter current command I _c ^* by amplifying the error △ E _d. An arithmetic unit 305 converts the AC converter current of the converter 18 into a DC converter current detection signal _Icf . An arithmetic unit 304 detects an error _ΔIc between the converter current command I _c ^* and the converter current detection signal I _cf. An amplifier 306 amplifies the error ΔIc and outputs a converter voltage command V _c ^* . 310 is a converter gate circuit operates by receiving a converter voltage command V _c ^* and the winding primary voltage phase theta ₁ of the linear induction generator 12, the frequency of the output voltage of the converter 18 is defined by the primary voltage phase theta _1, control signal of the switch elements 181U~181Z converter 18 such that the magnitude to generate a voltage that is indicated by the voltage command _V ^{c *} 3
Generate 10U-310Z.

Reference numeral 320 denotes a converter control logic for suppressing a normal gate control signal to the converter 18 when receiving the first accident detection signal 40S, the details of which are shown in FIG. In FIG. 6, reference numerals 321U to 321Z denote AND circuits.
The control signals 310U to 310Z generated from the first accident detection signal 40S are input to the other input.
When the first accident signal 40S is generated, the passage of the control signals 310U to 310Z is prohibited and the converter 18 is stopped.

Next, the overall operation of the operation control device for a wound-type induction generator according to the present embodiment configured as described above will be described.

First, the wound induction generator 12 is connected to the power transmission system 1.
The operation in the steady state, in which the generated power is sent to the power system, is as follows.

In FIG. 1, the secondary winding of the wound induction generator 12 is secondary-excited by an inverter 14 controlled based on a current command value I ₂ ^*, and the DC buses 13P and 13N of the inverter 14 A DC capacitor 16 is connected, and a converter 18 for receiving AC power from the primary winding of the wound induction generator 12 and converting the AC power into DC power is connected. The converter 18 converts the DC bus voltage into a DC voltage command value E.
_{Since the} control is performed so as to match _d ^* , a voltage having a frequency equal to the transmission line frequency is generated in the primary winding of the wound induction generator 12, and the power is transmitted to the power transmission system 13 via the main transformer 11. Supplied.

In the variable speed power generation system using the above-described conventional cycloconverter as the secondary excitation source, the cycloconverter generates a large reactive power on the input power source side, and this reactive power is generated by the wound induction generator 12. Since the power must be supplied from the primary winding, the capacity of the wound induction generator 12 increases, and the input current of the cycloconverter includes many harmonics, which causes distortion of the generated voltage. It has become. On the other hand, in the present embodiment, converter 18 is connected to DC bus 13P,
Since the voltage of 13N is controlled to be kept constant, in the converter 18, only the active power induced on the secondary side of the winding induction generator 15 flows to the AC lines 21U to 21W. For the primary winding of the wound induction generator 12, the supply of reactive power, which was required in the conventional cycloconverter system, is no longer required in the system using the converter 18. As a result, the capacity of the wound induction generator 12 is reduced. Can be made smaller than in the cycloconverter system. In addition, since converter 18 is normally operated by the PWM control method, the current flowing through AC lines 21 to 21W contains almost no harmonic components, and as a result, the voltage distortion of the generated voltage can be remarkably reduced.

Next, the operation when an accident occurs in the power transmission system 11 or the like is as follows.

That is, the inverter 14 and the converter 1
The chopper 15 is installed on the DC buses 13P and 13N connecting the DC bus 8 and the DC bus 1 in the chopper control circuit 200.
The DC voltage further rises despite the gate signal 205S of the chopper 15 for controlling the ON / OFF of the chopper 15 in accordance with the voltages of the 3P and 13N to suppress the rise of the DC voltage, and the DC voltage rise suppression means by the chopper 15. In this case, a comparator 204 for detecting this and generating a short-circuit mode signal 204S is provided, and a first and second fault detector 4 for detecting occurrence of a fault in the power transmission system 11 or the like.
0 and 50 are installed to obtain a first fault signal 40S and a second fault signal 50S, which are respectively converted by the converter control logic 320 and the inverter control logic 12S.
It works on zero.

By the way, in the above-mentioned variable speed power generation system for performing secondary excitation by the conventional cycloconverter,
The following problems occur when an accident such as lightning damage occurs in the power transmission system. In other words, when a short-circuit accident or the like occurs on the transmission line due to lightning damage, a negative-phase component is put on the transmission line, and the cycloconverter becomes inoperable and stops. Since the high voltage is induced and applied to the thyristor element constituting the cycloconverter, the thyristor may be damaged. Therefore, in the system shown in FIG. 7, when operating in a power system where lightning damage frequently occurs, it is necessary to operate this system with due care. On the other hand, in the present embodiment, the following operation is performed when an accident occurs in a transmission line or the like. First, when the second fault detector 50 detects a transmission line fault, the normal gate signal to the inverter 14 is stopped by the second fault signal 50S. In this state, the secondary winding current of the wound induction generator 12 flows through the diodes 142U to 142Z constituting the inverter 14, charges the DC capacitor 16, and the DC capacitor voltage tends to increase. In such a state, if converter 18 is stopped, the function of maintaining the DC capacitor voltage at a constant value is lost, and the DC voltage rises to a value that destroys the switching elements constituting inverter 14 and converter 18. . Therefore, in order to avoid such a situation, the present embodiment operates as follows to prevent the DC voltage from rising.

That is, in the event of a transmission line accident, the second
At the same time as the accident detector 50, the first accident detector 40 detects a transmission line accident. When the primary voltage of the generator becomes smaller than a predetermined value, the first accident detector 40 A first fault signal 40S is generated, but the first fault signal 40S is not generated when the primary voltage of the generator is higher than a predetermined value. When the first fault signal 40S is generated, the converter The normal gate signal to 18 is stopped. Accordingly, when the primary voltage of the generator is higher than the predetermined value and the first fault signal 40S is not generated at the time of the transmission line fault, it is normal that the voltage of the DC bus is going to increase as the first stage. Is controlled so as to prevent an increase in voltage.

Next, when the primary voltage of the generator at the time of the transmission line accident is smaller than a predetermined value, the first accident signal 40S
Occurs, the DC voltage maintaining function of the converter 18 is lost to stop the normal gate signal of the converter 18 and the DC voltage tends to increase. In this case, the chopper control is performed as the second stage. The comparator 204 of the circuit 200 detects the rise of the DC voltage, and turns on and off the chopper 15 to control the rise of the DC voltage.

Next, in the case where the DC voltage is about to rise further despite the suppression of the DC voltage rise by the chopper 15, as a third step, the increase in the DC voltage is compared in the chopper control circuit 200. The short-circuit mode signal 204S is detected by the detector 204, and the switching elements 141U, 141V, 1
41W (or switch elements 141X, 141Y, 14
1Z) at the same time. In such a state, the secondary windings of the wound induction generator 12 are the elements 141U, 141V, 141 constituting the inverter 14.
W, 142U, 142V, 142W (or the element 14
1X, 141Y, 141Z, 142X, 142Y, 14
2Z), the current in the secondary winding does not flow into the DC capacitor 16 and the DC voltage can be prevented from rising.

Accordingly, in the operation control device of the wound induction generator according to the present embodiment, the high voltage due to the rise of the DC bus voltage is supplied to the excitation means for the secondary excitation of the wound induction generator 12 in the case of a transmission system accident or the like. Is applied,
The combination of DC voltage control, chopper control, and short-circuit mode control of the inverter 14 by the converter 18 can reliably prevent an abnormal rise in DC voltage. This is performed reliably, and the reliability when the variable speed power generation system is operated in parallel with the system can be improved. That is, since the excitation means can be reliably protected at the time of a transmission system failure or the like, it operates stably both in a steady state and during a transient state of a transmission line failure, and supplies reliable and high-quality power to the transmission system 13. Can supply.

As described above, in the present embodiment, the winding type induction generator is connected to the secondary winding of the winding type induction generator 12, receives power from the DC bus 13P, converts DC power into AC power, and converts the DC power into AC power. , A chopper circuit 15 installed on the DC bus of the inverter 14, a DC capacitor 16 installed on the DC bus, and a primary winding of the wound induction generator 12. A converter 18 receives power supply from the line side via a transformer 11, converts AC power into DC power, and supplies DC power to a DC bus 13 </ b> P, and an inverter 14 is connected to a secondary winding of the wound induction generator 12. The inverter 14 is controlled to supply a predetermined secondary current.
Control circuit 100 for controlling power supply and converter 1
8 controls a converter so that the DC voltage of the DC bus 13P is maintained at a predetermined value, and a chopper that turns on and off the chopper 15 according to the voltage of the DC bus 13P to suppress an increase in the DC bus voltage. Control circuit 200 and chopper control circuit 200 for controlling
The comparator 20 detects that the DC voltage has further risen despite the DC voltage rise suppression means by the chopper and generates a short-circuit mode signal 204S to the inverter.
4 and the primary winding voltage of the wound induction generator 12 is introduced through the voltage detecting transformer 22 to monitor the change in the primary winding voltage at the time of an accident such as a power transmission line.
The first fault detector 40 that outputs 0S and the primary winding voltage of the wound induction generator 12 are introduced through the voltage detection transformer 22 to monitor the change in the primary winding voltage at the time of a fault in a transmission line or the like. To output the second accident signal 50S in the event of an accident
When the second fault detection signal 50S is received within the fault detector 50 and the inverter control circuit 100, the normal gate control signal to the inverter is suppressed, and the short-circuit mode signal 2
Inverter control logic 120 for controlling to simultaneously supply ON commands to switch elements 141U, 141V, 141W (or switch elements 141X, 141Y, 141Z) constituting inverter 14 when receiving 04S.
And converter control logic 320 for suppressing a normal gate control signal to converter 18 when receiving first accident detection signal 40S in converter control circuit 300.
It is composed of the following.

Therefore, the capacity of the winding induction generator 12 can be reduced, the voltage distortion at the time of power generation is small, and the excitation means is reliably protected even in the event of an abnormality such as a transmission line system accident. In addition, it is possible to stably operate even during a transient phenomenon and supply high-quality power to the power transmission system 13.

[0045]

As described above, according to the present invention, the exciting means for exciting the secondary winding of the wound induction generator converts the DC power into the AC power by receiving the power supply from the DC bus. An inverter that supplies the secondary winding, a converter that receives power supply from the primary winding side of the winding induction generator via a transformer, converts AC power into DC power, and supplies DC power to the DC bus, Since it consists of a DC capacitor installed on the bus, a resistor and a switching element, and a chopper installed on the DC bus, the capacity of the generator can be reduced, and the voltage distortion during power generation is small, and Operation of an extremely reliable wound-type induction generator that can reliably protect the excitation means and supply high-quality power to the power transmission system even in the event of an abnormality such as a power transmission line accident. Control device It can be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of an operation control device for a wound-type induction generator according to the present invention.

FIG. 2 is a diagram for explaining a function of a first accident detector in the embodiment.

FIG. 3 is a diagram for explaining a function of a second accident detector in the embodiment.

FIG. 4 is an exemplary view for explaining the function of the inverter control logic in the embodiment.

FIG. 5 is a view for explaining functions of the chopper control circuit in the embodiment.

FIG. 6 is a diagram for explaining a function of a converter control logic in the embodiment.

FIG. 7 is a block diagram showing a configuration example of a variable speed power generation system using a conventional cycloconverter.

[Explanation of symbols]

1, 2, 3, 4 ... transmission line, 5 ... power system, 6, 7, 8,
9: circuit breaker, 10: power generation plant, 11: main transformer,
12 ... winding type induction generator, 13 ... power transmission system, 13P, 1
3N DC bus, 14 inverter, 15 chopper circuit, 151 resistor, 152 switch element, 16 DC capacitor, 17 transformer, 18 converter, 19
U, 19V, 19W ... secondary current detector, 20 ... DC voltage detector, 21U, 21V, 21W ... converter current detector, 22 ... voltage detection transformer, 30 ... voltage phase detector,
31 ... rotor phase detection circuit, 32 ... calculator, 40 ... first
, An accident detector 50, a second accident detector 100, an inverter control circuit 120, an inverter control logic 2,
00: chopper control circuit, 204: comparator, 300: converter control circuit, 320: converter control logic.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mitsuyuki Abe 1-3-1, Uchisaiwaicho, Chiyoda-ku, Tokyo Tokyo Electric Power Company (72) Inventor Hirokazu Kaneko 1-3-1, Uchisaiwaicho, Chiyoda-ku, Tokyo Tokyo Inside Electric Power Company (72) Inventor Ryoji Sugawara 6-15-1, Ginza, Chuo-ku, Tokyo Inside Power Development Co., Ltd. (72) Inventor Masakazu Kobayashi Power Supply Development Co., Ltd., 6-15-1, Ginza, Chuo-ku, Tokyo (72) Inventor Takeo Shimamura 1 Toshiba-cho, Fuchu-shi, Tokyo Inside Fuchu Plant, Toshiba Corporation

Claims (1)

(57) [Claims] 1. A primary winding of a wound induction generator having a primary winding and a secondary winding is connected to a power transmission system via a transformer, and the secondary winding is excited by exciting means to generate electric power. In the device for controlling the operation of the wound induction generator that supplies power to the power transmission system, connected to the secondary winding of the wound induction generator, receives DC power from the DC bus and converts DC power An inverter that converts AC power to supply the secondary winding; a converter that converts AC power to DC power to supply DC power to the DC bus; a DC capacitor installed in the DC bus; A chopper installed on a bus, control means for controlling the converter and, if necessary, an inverter so as to suppress an increase in the DC bus voltage when an occurrence of an accident in the power transmission system is detected; An operation control device for a winding-type induction generator, comprising: chopper control means for controlling the chopper so as to suppress an increase in the DC voltage when an abnormal rise in the voltage of the flow bus is detected.