JPH1198872A - Thyristor starter for synchronous machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To economize the capital investment of a thyristor starter for a synchronous machine. SOLUTION: Starters 1a and 1b have the same constitution and have capacities which are about the half the capacity required for starting one synchronous machine 8 with one thyristor starter. The starters 1a and 1b are connected to the synchronous machine 8 respectively through disconnecting switches 7a and 7b which respectively connect different shafts of synchronous machines 8, so that the starters 1a and 1b can supply electric currents to either machine 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thyristor starting device for a synchronous machine.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram of a conventional thyristor starting device.

In the figure, 1 is a starting device, 2 is an input transformer, 3 is a forward converter, 4 is a DC reactor, 5 is a reverse converter, 6 is an AC reactor, 7 is the thyristor starting device 1 and synchronization of each axis. This is a disconnector for connecting the machine 8. Each of the forward converter 3 and the inverse converter 5 is a three-phase rectifier composed of a thyristor element. The synchronous machine 8 is connected to the thyristor starting device 1 via an AC reactor 9, and a speed pulse generator 11 is provided on the shaft. Further, the input transformer 2
, A forward converter synchronous power transformer 12 is provided on the primary side, a current transformer 13 for current detection is provided on the AC side of the forward converter 3, and an inverter is provided on the output side of the AC reactor 6. A synchronous power transformer 14 is provided.

The speed detector 15 receives a pulse signal having a frequency proportional to the rotation speed ω of the synchronous machine 8 output from the speed pulse generator 11 and outputs a synchronous machine speed signal ω. The speed adjuster 16 receives the synchronous machine speed signal ω and the speed set value ωr, amplifies the deviation signal, and outputs a current reference signal Ir. The current detector 17 rectifies the AC output of the current transformer 13 and outputs a converter current signal I proportional to the converter current Id. The current regulator 18 receives the current reference signal Ir and the converter current signal I, amplifies the deviation signal, and outputs a forward converter phase control signal Θr1.

A forward converter pulse generator 19 receives the AC output of the forward converter synchronous power transformer 12, detects the synchronous power supply phase Θ1, and receives a forward converter phase control signal Θr1 at a timing corresponding to Θr1. The firing pulse signal P1 is sequentially output to each thyristor element of the forward converter 3. The voltage detector 20 rectifies the AC output of the inverter synchronous power transformer 14 and outputs an inverter voltage signal V2.

The margin angle controller 21 receives the synchronous machine speed signal ω, the converter current signal I, the inverter voltage signal V2, the margin angle set value γ2, and the commutation inductance L, and inverts according to the following equation (1). An inverter phase control signal Θr2 that outputs the commutation overlap angle of the converter 5 is output.

[0007]

(Equation 1)

Here, (1) commutation inductance L = inductance of AC reactor 6 + inductance of AC reactor 9 + inductance of synchronous machine 8 (2) L, ω, I, and V2 are all expressed in PU values.

The inverter pulse generator 22 receives the AC output of the inverter synchronous power transformer 14, detects the synchronous power phase Θ2, and receives the inverter phase control signal Θr2 at a timing corresponding to Θr2. The firing pulse signal P2 is sequentially output to each thyristor element of the inverter 5.

While the synchronous machine 8 is accelerated from a stopped state or a low rotational speed state at the time of turning to a predetermined rotational speed, the output voltage Vg of the synchronous machine 8 does not reach a sufficiently large value, so that an inverter pulse is generated. The detector 22 cannot detect the synchronous power supply phase # 2. Therefore, while the synchronous machine 8 is accelerated from the stop state or the turning state to a predetermined rotational speed, the inverter 5 is accelerated based on a rotor position signal output from a separately provided rotation preposition detector of the synchronous machine 8. Is generated.

When a predetermined field current is applied to the field winding of the synchronous machine 8, an output voltage Vg proportional to the rotation speed ω is induced. The inverter 5 performs an inverter operation using the output voltage Vg as an AC power supply to supply power to the synchronous machine 8. On the DC side of the inverter 5, an inverter DC voltage VDC2 corresponding to the output voltage Vg of the synchronous machine 8 and the inverter phase control signal Θr2 appears. The forward converter phase control signal Θr1 is adjusted so that the signal I matches the current reference signal Ir, and the forward converter DC voltage VDC is adjusted.
Control 1 The speed adjuster 16 increases or decreases the current reference signal Ir so that the synchronous machine speed signal ω matches the set speed value ωr, and maintains the synchronous machine 8 at a predetermined rotation speed.

The input transformer 2 converts the voltage level and protects the thyristor element of the forward converter 3 from short-circuit current, the DC reactor 4 suppresses the ripple of the converter current Id, and the AC reactor 6 performs reverse conversion. It is provided to protect the thyristor element of the heater 5 from short-circuit current.

In a combined cycle plant, a thyristor starting device is generally installed on each shaft of the gas turbine generator as a multi-shaft configuration having about four or more gas turbine generators. In this case, the synchronous machine 8 is connected to the starting device 1 and the starting operation is performed on a one-to-one basis.

First, at the time of starting the plant, the starting gas turbine generator of the first axis is started using one starting apparatus 1, and when the starting is completed sequentially, the starting apparatus 1 is switched to start the second axis and the third axis. .

[0015]

However, if a plurality of large-capacity thyristor starting devices 1 required when starting the first axis after stopping all the axes are prepared as in the prior art, the number of the thyristor and the equipment as a whole are increased. There is a problem that it is uneconomical in terms of capacity. In other words, the capacity required to start the second and third axes is less than half the required capacity when starting the first axis after stopping all axes if auxiliary steam such as the already started first axis is used. Therefore, effective utilization of energy and effective capital investment have been desired.

Accordingly, an object of the present invention is to provide a thyristor starting device for a synchronous machine which prepares a plurality of starting devices having a small capacity and sequentially starts a plurality of axes.

[0017]

According to the first aspect of the present invention, there is provided a forward converter for converting an alternating current to a direct current by a pulse control signal based on a forward converter phase control signal, and an inverse converter for converting a direct current output of the forward converter. A separately-excited inverter using a thyristor element to convert the AC power into a variable frequency by a pulse control signal based on a phase control signal and supply the AC power to a synchronous machine, and a current command so that the frequency signal of the synchronous machine becomes a frequency command signal. A speed regulator for generating a signal, a current regulator for outputting a forward converter phase control signal so that the current signal of the forward converter becomes the current command signal, and a commutation overlap angle and the preset reverse. A plurality of starting devices each including a controller for calculating and outputting a margin angle control signal in consideration of a commutation overlap angle from a commutation margin angle of the converter, and one or more synchronous devices are appropriately provided. Start It is obtained by way. According to this means, when one synchronous machine is started by a plurality of starting devices, the converter current necessary for starting one synchronous machine by the plurality of starting devices as a whole may be supplied. The converter current shared by each starting device can be a value obtained by dividing the current required for the entire starting by the number of operating units, and the equipment capacity of each starting device can be significantly reduced. When the initial axis is operated after stopping all axes, a large starting current is supplied as a whole by a plurality of small-capacity starting devices. When sequentially operating two axes and three axes, one small-capacity starting device is used. It can be started by connecting and using a small amount of starting current by using the auxiliary steam. This greatly reduces equipment capacity and the number of units compared to the conventional installation of multiple large-capacity starters and starting one synchronous machine for one starter. The equipment can be installed economically.

According to a second aspect of the present invention, in the thyristor starting device for a synchronous machine according to the first aspect, the margin angle controller comprises:
There is provided a setting means for setting and inputting a commutation inductance according to the number of operating starter devices, and a calculation means for setting a value obtained by executing a calculation based on the set commutation inductance as the commutation overlap angle. It was done. According to this means, the commutation inductance is set according to the number of operating starter devices, and is controlled by the commutation overlap angle corresponding to the calculated number of operating devices. As a result, commutation failure can be prevented beforehand as the commutation overlap angle increases and the margin angle decreases, and operation can always be performed with high efficiency.

According to a third aspect of the present invention, in the thyristor starting device for a synchronous machine according to the first aspect, the margin angle controller includes:
Setting means for setting and inputting a commutation inductance corresponding to the number of operating starter units, and performing an operation based on the set and input commutation inductance and an amount corresponding to a current supplied to the synchronous machine, and a value obtained. Is provided for calculating the commutation overlap angle. According to this means, the current supplied to the synchronous machine and the commutation inductance are set according to the number of operating starter devices, and the commutation overlap angle corresponding to the calculated number of operating machines and the current of the synchronous machine is controlled. You. As a result, commutation failure can be prevented beforehand as the commutation overlap angle increases and the margin angle decreases, and operation can always be performed with high efficiency.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a thyristor starting device according to a first embodiment of the present invention. The capacity required for starting one gas turbine generator with only one thyristor starting device is shown. It is characterized in that two thyristor starting devices of about half of the above are installed and switched appropriately, and each starting device can supply current to any gas turbine generator.

Here, the starting device 1a and the starting device 1b have the same configuration, and the same components are distinguished by the suffixes a and b. Hereinafter, the starting device 1a will be described. In FIG. 1, 2a is an input transformer, 3a is a forward converter, 4a is a DC reactor, 5a is an inverse converter, 6a is an AC reactor,
Reference numeral 7a denotes a disconnecting device that connects the starting device 1a and the synchronous machine 8 of each axis. Each of the forward converter 3a and the inverse converter 5a is a three-phase rectifier composed of a thyristor element. The synchronous machine 8 of each axis is connected to the starting device 1a via the AC reactor 9 and the disconnector 10.
A speed pulse generator 11a is provided on the shaft while being connected to the starting device 1b.

Further, a forward converter synchronous power supply transformer 12a is provided on the primary side of the input transformer 2a, a current detecting current transformer 13a is provided on the AC side of the forward converter 3a, and an output side of the AC reactor 6a is provided. Is provided with an inverter synchronous power transformer 14a.

The speed detector 15a is a speed pulse generator 11
A pulse signal having a frequency proportional to the rotation speed ω of the synchronous machine 8 output by the signal a is input to output a synchronous machine speed signal ωa. The speed adjuster 16a receives the synchronous machine speed signal ωa and the speed set value ωr.
a, and amplifies the deviation signal to output a current reference signal Ira. The current detector 17a rectifies the AC output of the current transformer 13a and converts a converter current signal I proportional to the converter current Ida.
a is output. The current regulator 18a receives the current reference signal Ira
And a converter current signal Ia, and amplifies the deviation signal to output a forward converter phase control signal Θr1a.

The forward converter pulse generator 19a receives the AC output of the forward converter synchronous power transformer 12a and receives the synchronous power phase Θ.
1a and the forward converter phase control signal {r1a
At the timing corresponding to Θr1a.
The firing pulse signal P1a is sequentially output to each thyristor element.

The voltage detector 20a rectifies the AC output of the inverter synchronous power transformer 14a and outputs an inverter voltage signal V2a.

The margin angle controller 21a outputs the synchronous machine speed signal ωa
And the converter current signal Ia, the inverter voltage signal V2a, the margin angle set value γ2a, and the commutation inductance La, and in accordance with the following equation (2), an inverter that takes into account the commutation overlap angle of the inverter 5 It outputs the phase control signal Θr2a.

[0028]

(Equation 2)

Here, La: commutation inductance La, ωa, Ia, V2a are all expressed in PU value.

The inverter pulse generator 22a receives the AC output of the inverter synchronous power transformer 14a and receives the synchronous power phase Θ.
2a and the inverter phase control signal {r2a
And sequentially outputs a firing pulse signal P2a to each thyristor element of the inverter 5 at a timing corresponding to Θr2a.

When a predetermined field current flows through the field winding of the synchronous machine 8, an output voltage Vg proportional to the rotation speed ωa is induced. The inverter 5a performs an inverter operation using the output voltage Vg as an AC power supply to supply power to the synchronous machine 8. On the DC side of the inverter 5a, the inverter DC voltage VD according to the output voltage Vg of the synchronous machine 8 and the inverter phase control signal Θr2a is provided.
Although C2a appears, the current regulator 18a controls the forward converter DC voltage VDC1a by adjusting the forward converter phase control signal Θr1a so that the converter current signal I matches the current reference signal Ira. Speed adjuster 16a
Increases / decreases the current reference signal Ira so that the synchronous machine speed signal ωa matches the speed set value ωra, and maintains the synchronous machine 8 at a predetermined rotational speed.

Although the starter 1a has been described above, the starter 1b has the same configuration.

With this configuration, when starting the plant, the gas turbine generator of the first shaft is started using two thyristor starting devices, and after the second shaft, the gas is supplied from one thyristor starting device and the operating shaft. Start sequentially with auxiliary steam. In a combined cycle plant, it is rare that all axes are stopped. Therefore, after starting the first axis, two axes can be started using two starters and auxiliary steam from the operating axes.

As described above, according to the first embodiment, when one synchronous machine is started by two starting devices, it is necessary for one synchronous machine to be started by the two starting devices as a whole. Since the converter current only needs to be supplied, the converter current shared by each starter can be a value obtained by dividing the current required for the entire start by the number of operating units, and the installed capacity of each starter can be greatly reduced. Can be smaller. When the initial axis is operated after stopping all axes, a large starting current is supplied as a whole by a plurality of small-capacity starting devices. When sequentially operating two axes and three axes, one small-capacity starting device is used. It can be started by connecting and using a small amount of starting current by using the auxiliary steam. As a result, the equipment capacity and the number of units can be greatly reduced as compared with the conventional case where a plurality of large-capacity starters are installed and one synchronous machine is started for one starter. The equipment can be installed economically.

FIG. 2 is a configuration diagram of a thyristor starting device according to a second embodiment of the present invention.

FIG. 2 is different from FIG.
3a and 23b. The switch 23a switches the commutation inductance L1a during operation of one unit and the commutation inductance L2a during operation of two units, and sets the commutation inductance La to the margin angle controller 21a. When the operation instruction C2a for two units is off, one unit is operated. The time commutation inductance L1a is output as the commutation inductance La, and the two-unit operation command C2
When a is on, commutation inductance L2a during operation of two units
Is output as the commutation inductance La.

Here, the commutation inductance L when one vehicle is operating
1a is set in advance as in the following equation (3).

[0038]

Similarly, the commutation inductance L during one-unit operation
1b is set in advance as in the following equation (4).

[0040]

On the other hand, when the two units are operated, the commutation inductance L2
As for a, for example, assuming that the starting devices 1a and 1b perform the same operation with the same converter current to supply the current I to the synchronous machine 8, the AC reactor 6
Converter current I / 2 flows to a and AC reactor 6b, and combined converter current I flows to AC reactor 9 and synchronous machine 8. Assuming this, the commutation inductance L2a during two-car operation is equivalently expressed by the following equation (5) and is set in advance.

[0042]

Similarly, the commutation inductance L during operation of two units
2b is represented by the following equation (6) and is set in advance.

[0044]

According to the above-described configuration, the switching device 23a and the switching device 23a are used depending on whether the number of starting devices for starting the synchronous machine is one or two.
Actual commutation inductance L selected by switch 23b
a, since the margin angle control can be performed based on the commutation inductance Lb, the margin angle of the inverter can be matched with the margin angle set value γ2a in any case.

As described above, according to the second embodiment, the first
In addition to the effects of the embodiment, even if the number of starting devices for starting the synchronous machine changes, the margin angle control of the inverter can be performed based on the actual commutation inductance. Failures can be prevented and the starting device can be operated at a high power factor.

FIG. 3 is a configuration diagram of a thyristor starting device showing a third embodiment of the present invention.

3 is different from FIG. 1 in that a switching device 24a is additionally provided in the starting device 1a, and a margin angle controller 21 is provided.
a margin angle controller 25a having a configuration different from
A switching device 24b is added to the starting device 1b, and the margin angle controller 2
1b is provided with a margin angle controller 25b having a different configuration from that of FIG.

The switch 24a receives the converter current signal Ib of the other starting device 1b and the two-unit operation command C2a, outputs 0 when the two-unit operation command C2a is off, and outputs the two-unit operation command C2.
When 2 is on, the transformer flow signal Ib is output as the other device converter current signal Iba. The margin angle controller 25a includes a synchronous machine speed signal ωa, a converter current signal Ia, an inverter voltage signal V2a, a margin angle set value γ2a, another device converter current signal Iba, and an inductance L1a of the AC reactor 6a.
And the inductance L2 of the AC reactor 9, and outputs an inverter phase control signal Θr2a in consideration of the commutation overlap angle of the inverter 5a by an operation described later.

The switch 24b receives the transformer current signal Ia of the other starting device 1a and the two-unit operation command C2b, outputs 0 when the two-unit operation command C2b is off, and outputs the two-unit operation command C2.
When b is on, the converter current signal Ia is output as the other device converter current signal Iab. The margin angle controller 25b
Synchronous machine speed signal ωb, converter current signal Ib, inverter voltage signal V2b, margin angle set value γ2b, other device converter current signal Iab, and inductance L1 of AC reactor 6b
b and the inductance L2 of the AC reactor 9 are input, and an inverter phase control signal Θr2b that outputs the commutation overlap angle of the inverter 5b is output by an operation described later.

Here, the margin angle controller 25a calculates according to the following equation (7) and outputs the obtained inverse converter phase control signal Θr2a to the inverter pulse generator 22a.

[0052]

(Equation 3)

Where ωa, Ia, V2a, L1a, L
2 and Iba are both PU value expressions. L1a: Inductance of AC reactor 6a L2: Inductance of AC reactor 9 Ia: Converter current of starting device 1a Iba: Converter current signal of starting device 1b In the above equation (7), the inductance of synchronous machine 8 is ignored. I have.

The margin angle controller 25b calculates according to the following equation (8) and outputs the obtained inverse converter phase control signal Θr2b to the inverter pulse generator 22b.

[0055]

(Equation 4)

Where ωb, Ib, V2b, L1b, L
2 and Iab are both PU value expressions. L1b: Inductance of AC reactor 6b L2: Inductance of AC reactor 9 Ib: Converter current of starting device 1b Iab: Converter current signal of starting device 1a In the above equation (7), the inductance of synchronous machine 8 is ignored. I have.

According to the above configuration, when the number of starting devices for starting the synchronous machine 8 is one, the starting devices 1a and 1
When only one of b is operated, the other device converter current signals Iba and Iab become 0. Either the starting device 1a or the starting device 1b is provided with a commutation inductance L1a +
The margin angle control can be performed based on L2 or L1b + L2.

On the other hand, when the starter 1a and the starter 1b are both operated and two units are used, the other device converter current signal Iba,
The margin angle control can be performed based on the fact that the converter current corresponding to the other device converter current signal Iab flows into the AC reactor 9 by another starting device and takes into account the total Iab + Iba equivalent.

As described above, according to the third embodiment, the first
In addition to the effects of the embodiment, even when the number of starting devices for starting the synchronous machine changes and the converter currents of the two starting devices are different, the margin angle of the inverter can be based on the actual commutation inductance. Since the control can be performed, commutation failure of the inverter can be prevented, and the starting device can be operated at a high power factor.

In the embodiment of the present invention, two starting devices have been described. However, the synchronous machine can be similarly started by three or more starting devices.

[0061]

As described above, according to the first aspect of the present invention, a single synchronous machine is started by a plurality of relatively small-capacity starting devices. The installation capacity and the number of units can be greatly reduced compared to the conventional installation of multiple large-capacity starting devices and starting one synchronous machine for one starting device. Reduction can be achieved and economic equipment can be introduced.

According to the second aspect of the present invention, the commutation inductance is set according to the number of operating starter devices, and the commutation overlap angle is controlled according to the number of operating devices, so that the commutation overlap angle increases. Therefore, commutation failure due to a decrease in the margin angle can be prevented beforehand, and operation can always be performed with high efficiency.

According to the third aspect of the present invention, the current supplied to the synchronous machine and the commutation inductance are set in accordance with the number of operating starters, and the commutation overlap angle corresponding to the number of operating machines and the current of the synchronous machine is set. , The commutation overlap angle increases and the commutation failure can be reliably prevented with a decrease in the margin angle,
It can always operate with high efficiency.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a thyristor starting device for a synchronous machine according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a thyristor starting device for a synchronous machine according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a thyristor starting device for a synchronous machine according to a third embodiment of the present invention.

FIG. 4 is a configuration diagram of a conventional thyristor starting device for a synchronous machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Starter 2 Input transformer 3 Forward converter 4 DC reactor 5 Inverter 6 AC reactor 7 Disconnector 8 Synchronous machine 11 Speed pulse generator 12 Forward converter synchronous power transformer 13 Current transformer 14 Inverter synchronous power supply Transformer 15 Speed detector 16 Speed adjuster 17 Current detector 18 Current adjuster 19 Forward converter pulse generator 20 Voltage detector 21, 25 Margin angle controller 22 Inverter pulse generator 24 Switch

Claims (3)

[Claims] 1. A forward converter for converting an alternating current into a direct current by a pulse control signal based on a forward converter phase control signal, and a variable frequency controlled by a pulse control signal based on an inverse converter phase control signal. A separately-excited inverter using a thyristor element that converts the AC power into AC power and supplies the AC power to a synchronous machine; a speed regulator that generates a current command signal so that the frequency signal of the synchronous machine becomes a frequency command signal; A current regulator for outputting a forward converter phase control signal so that the current signal of the converter becomes the current command signal; and a commutation based on a commutation overlap angle and a preset commutation allowance angle of the inverter. A synchronous machine characterized by comprising a plurality of starting devices comprising a margin angle controller for calculating and outputting a margin angle control signal in anticipation of an overlap angle, and appropriately starting one or a plurality of the synchronous machines. Cyris Starter. 2. The margin angle controller comprises: setting means for setting and inputting a commutation inductance according to the number of operating starter devices; and a value obtained by executing a calculation based on the set commutation inductance. 2. The thyristor starting device for a synchronous machine according to claim 1, further comprising a calculating means for calculating a commutation overlap angle. 3. The margin angle controller includes: a setting unit configured to set and input a commutation inductance corresponding to the number of operating starter devices; and a commutation inductance set and input corresponding to a current corresponding to a current supplied to the synchronous machine. 2. The thyristor starting device for a synchronous machine according to claim 1, further comprising: an arithmetic unit that executes an arithmetic operation based on the above equation and uses the obtained value as the commutation overlap angle.