JPS6155353B2 - - Google Patents

Description

[Detailed Description of the Invention] When a synchronous motor is synchronously connected to a power system, the supply of field current is stopped when the parallel circuit breaker is not turned on within a certain time period even if a closing command is given. The present invention relates to a synchronous motor device.

Conventionally, as a synchronous motor device, the synchronous motor is started using starting power supplied from a static power converter, and when synchronization conditions with the power grid are established, the supply of starting power from the static power converter is stopped. There is also a system that connects the synchronous motor to the power grid by inserting a parallel switch or disconnector so that the synchronous motor can be operated using grid power. The static power converter is connected to a power supply circuit, and controls the rotational speed of the synchronous motor to a synchronous speed by controlling the magnitude of starting power supplied to the synchronous motor through gate control of a thyristor. in this case,
For the purpose of shortening the startup time of synchronous motors and suppressing abnormal phenomena that occur when short-circuit currents or commutation failures occur in power systems, synchronous motors, and static power converters,
The field current of the synchronous motor is kept constant when the synchronous motor is started, and the field current is controlled so that the terminal voltage of the synchronous motor becomes constant when a specified rotation speed is reached.

However, in such a synchronous motor device,
When a synchronous motor is started and then synchronously connected to the power grid, if the parallel disconnector is not turned on even though a turn-on command is given, the power supply to the synchronous motor will be cut off and the rotation speed will gradually decrease. descend. On the other hand, at this time, the field current of the synchronous motor shifts to control such that the terminal voltage is constant, so as the terminal voltage of the synchronous motor decreases, the field current increases more and more, and the synchronous motor and There is a risk that the transformer connected to the field control device that controls the field of the synchronous motor may become overexcited and burn out.

This invention was made in consideration of the above-mentioned circumstances, and its purpose is to synchronize the synchronous motor into the power system, even if a power-on command is given to the parallel switch or disconnector, within a certain period of time. If this parallel circuit breaker is not turned on, the supply of field current to the synchronous motor is stopped, thereby reliably preventing overheating and burnout of the synchronous motor and the transformer connected to it. Our objective is to provide a highly safe synchronous motor device.

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

FIG. 1 is a block diagram showing one embodiment of the present invention. In Fig. 1, 1 is a synchronous motor, and this synchronous motor 1 includes a position detector (not shown) that detects the relative position of the stator and rotor, and a rotation speed detection generator that detects the rotation speed. (not shown) is installed. The input end of this synchronous motor 1 is connected to the power supply bus 2 for supplying power to the system and to the disconnector 3.
It is connected to the static power converter 4 which receives the power via the starting liner and disconnector 5, and is connected to the power supply bus 2 via the parallel liner and disconnector 6. As the power conversion device 4, a frequency conversion device such as an inverter or a cycloconverter is used, and it supplies starting power to the synchronous motor 1 until the rotational speed of the synchronous motor 1 reaches the synchronous speed. Reference numeral 7 denotes a control signal converter which inputs the output signals of the position detector and the rotation speed detection generator to obtain a control signal. Reference numeral 8 denotes a speed control device which obtains drive power from the AC power supply bus 2 via a shingle breaker 3 and provides a thyristor gate control signal to the power conversion device 4 based on the control signal output from the control signal converter 7. . Note that the control signal converter 7 and speed control device 8 of the power conversion device 4 constitute a startup control device.

On the other hand, 9 is a DC converter that converts the AC power of the AC power source 10 into DC power, for example, by bridge-connecting a thyristor. It is intended to supply In addition, 13 is a field voltage adjustment device,
By inputting the set output of the constant excitation setting device 14 and the field voltage applied to the field winding 12, the control form of the synchronous motor 1 is set in the initial start control range (intermittent current start control range).
and field winding 12 until the first half of the constant current acceleration control region.
The DC converter 9 is controlled so that the voltage applied to the DC converter 9 becomes constant. Further, reference numeral 15 denotes an automatic voltage regulator that compares the terminal voltage of the synchronous motor 1 and the set output of the voltage setting device 16, and controls the DC converter 11 based on the comparison result. This control form performs constant terminal voltage control from the latter half of the constant current acceleration control region. Reference numeral 17 indicates an automatic adjustment device which inputs the output of the field voltage regulator 13 and the output signal of the automatic voltage regulator 15, and controls the set value of the voltage setting device 16 until the output signals of both regulators 13 and 15 become the same value. It is a speed device. In addition, 9-11 and 13-17
constitutes a field control device.

Reference numeral 18 denotes a synchronization verification device that inputs the terminal voltage of the synchronous motor and the voltage of the power supply bus 2, compares the voltage, frequency, and phase of each, and sends out an output signal when these fall within an allowable range for synchronization. The signal sent from this synchronization verification device 18 is sent to the voltage setter 16 as a voltage balance signal S1, and is sent as an equal speed signal S2.
The synchronization signal S3 is applied to the speed control device 8 as a synchronization signal S3, and to the synchronization confirmation device 20 of the disconnection control device 19 of the speed control device 8 as a synchronization signal S3. The shield breaker control device 19 is configured to control the starting shield breaker 5 of the power supply shield breaker 3 and the field shield breaker 1 of the parallel shield breaker 6.
1, and when the synchronizing signal S3 is given, the parallel circuit breaker 6
is turned on, and the power source disconnector 3 and starting disconnector 5 are tripped, and when the tripping signal S5 is given from the synchronization confirmation device 20, the field disconnector 11 is turned on.
It is used to remove the The synchronization confirmation device 20 is
When the closing signal S4 indicating that the parallel disconnector 6 has been turned on is not input from the disconnector control device 19 even after the closing time T has elapsed since the closing command was given to the parallel disconnector 6. , breaker control device 1
9, a tripping signal S is sent to trip the field and disconnector 11.
5.

Next, the operation of the device configured in this way will be explained. First, operate the shield breaker control device 19 to select the power shield breaker 3, the starting shield breaker 5, and the field shield breaker 1.
Insert 1. These wire breakers 3, 5 and 1
1 is shown in FIGS. 2a and 2b. The power supply bus 2 is disconnected from the power supply bus 2 by turning on the power supply disconnectors 3 and 5.
System power is supplied to the power conversion device 4 and the speed control device 8 via the power conversion device 4 and the speed control device 8. Then, the speed control device 8 gives a thyristor gate signal to the power conversion device 4,
Starting power is applied to the synchronous motor 1 via the power conversion device 4 and the mustard cutter 5 .

On the other hand, by turning on the field switch or disconnector 11, the field voltage regulator 13 performs gate control of the thyristor of the DC converter 9 so that the field voltage becomes the set value of the constant excitation setting device 14. As a result, the field winding 12 is excited to the set value set in the constant excitation setter 14, and the synchronous motor 1 is placed in a constant excitation state. When the synchronous motor 1 is started in a constant excitation state in this way, the difference between the torque generated by the armature current and field current of the synchronous motor 1 supplied from the power converter 4 and the reaction torque at that rotation speed is The rotational speed of the synchronous motor 1 increases due to the acceleration torque.

When the frequency supplied to the synchronous motor 1 reaches f ₁ (the first half of the constant current acceleration control region) as shown in FIG. The voltage setter 16 is controlled until the output signal with the voltage regulator 15 becomes the same.
When the frequency of the synchronous motor 1 reaches f ₂ (the latter half of the constant current acceleration control range), the field voltage adjustment device 13 changes from constant excitation control to automatic voltage adjustment that allows easy and fine voltage adjustment during constant speed control. The device 15 switches to constant terminal voltage excitation control (automatic voltage control) of the synchronous motor 1. In this case, automatic voltage regulator 1
The output signals of the field voltage regulator 5 and the field voltage regulator 13 match.

Here, when switching from constant excitation control by the field voltage regulator 13 to excitation control by the automatic voltage regulator 15, the output of the field voltage regulator 13 remains unchanged until the frequency of the synchronous motor 1 reaches _f2 . The signal generated and applied from the automatic voltage regulator 15 to the DC converter 9 is locked. Next, when the frequency of the synchronous motor 1 reaches _f2 , the lock of the signal given from the automatic voltage regulator 15 to the DC converter 6 is released, and at the same time, the field voltage regulator 1
Lock the output signal of 3. As a result, the field circuit can be smoothly switched without changing the DC current of the DC converter 9.

On the other hand, when the terminal voltage of the synchronous motor 1 reaches V1 as shown in FIG. 2h, the synchronization verification device 18 starts operating. The synchronous verification device 18 detects the system voltage of the power supply bus 2 and the terminal voltage of the synchronous motor 1,
The voltage setting device 16 is adjusted by applying a voltage balance signal S1 as shown in _FIG . Control the current. Also,
As mentioned above, when the terminal voltage of the synchronous motor 1 reaches V1, the synchronization detection device 18 supplies the speed control signal S2 as shown in FIG. 2d to the speed control device 8. Thereby, the speed control device 8 performs gate control of the power conversion device 4 so that the frequency of the synchronous motor 1 becomes equal to the system frequency f _L of the power supply bus 2. In this way, when the voltage difference, frequency difference, and phase difference between the terminal voltage of the synchronous motor 1 and the grid voltage are within the allowable values for synchronization, the synchronization verification device 18 generates a synchronization signal S3 as shown in FIG. 2e. is applied to the speed control device 8, the disconnection control device 19, and the synchronization confirmation device 20. As a result, the synchronization confirmation device 20 operates,
If the synchronizing switch 6 is closed within the closing time T, the field switch 11 remains closed as shown by the solid line in FIG. 2b. Further, the speed control device 8 stops gate control of the power conversion device 4 and turns off the thyristor gate. When the thyristor gate is completely disconnected, the sheath disconnectors 3 and 5 are tripped, and the synchronous motor 1 is switched from operating with the starting power supplied from the power converter 4 to the power source via the parallel sheath disconnector 6. Operation is switched to grid power supplied from bus 2, and continuous operation is performed.

On the other hand, even after the closing time T has elapsed since the synchronization verification device 18 outputs the synchronization signal S3 and the synchronization check device 20 operates, the closing signal S4 of the disconnector 6 does not continue as shown by the broken line in FIG. 2f. When the synchronization confirmation device 20 is not supplied from the switch breaker control device 19, a trip signal S5 as shown in FIG. 2g is given to the switch breaker control device 19. As a result, the control device 19 trips the field cutter 11, and the field current of the synchronous motor 1 is cut off.

Thus, according to this embodiment, the synchronous motor 1
When synchronization between the terminal voltage of the terminal voltage and the power system voltage has been established, and the closing command has been given to the parallel circuit breaker 6, but the circuit breaker 6 is not closed within the scheduled time T, this is synchronized. Since the input confirmation device 20 detects this and disconnects the field and the disconnector 11,
The field is not controlled so that the terminal voltage of the synchronous motor 1 becomes constant during automatic voltage operation by the automatic voltage regulator 15, and therefore the synchronous motor 1 and the transformer connected to the field control device become over-excited. As a result, these devices do not overheat or burn out, making them highly safe.

Note that this invention is not limited to the above embodiments. For example, the time from when the synchronization signal S3 is supplied to the synchronization confirmation device 20 to when the tripping signal S5 is given to the shunt breaker control device 19 needs to be set to the closing time T of the parallel shunt breaker 6. Not,
It may be set to a longer time than this time.

As explained above, according to the present invention, even if a closing command is given to the parallel switch or disconnector that synchronizes the synchronous motor to the power system, if the parallel switch or disconnector is not closed within a certain time period, Since the supply of field current to the synchronous motor is stopped, it is possible to provide a highly safe synchronous motor device that can prevent overheating and burnout of the synchronous motor and the transformer connected thereto. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 is a time chart for explaining the operation of the apparatus shown in FIG. 1...Synchronous motor, 2...Power bus, 3...Power supply line breaker, 4...Power converter, 5...Starting line breaker, 6...Parallel line breaker, 8... Speed control device, 9...DC converter, 11...Field shield and disconnector, 12...Field winding, 13...Field voltage regulator, 15...Automatic voltage regulator, 17...Automatic Speed equalization device, 18...Synchronization verification device, 19...Shipping switch control device, 20...Synchronization confirmation device.

Claims (1)

[Claims] 1. A synchronous motor connected to the power grid via a parallel disconnector, and a speed control device that sequentially performs startup control of this synchronous motor by dividing it into an initial startup control region, a constant current acceleration control region, and a uniform speed control region. and a starting control device including a static power converter, a field voltage adjustment device that performs constant terminal voltage excitation control of the synchronous motor until the first half of the starting control by the starting control device, and A field control device equipped with an automatic voltage adjustment device that performs constant excitation control of the terminal voltage of the motor, a synchronization verification device that performs synchronization verification between the terminal voltage of the synchronous motor and the grid voltage, and the synchronization verification device ensures that the synchronization condition is satisfied. a device for giving a closing command to the parallel shisha breaker when detected and stopping the supply of power from the start control device to the synchronous motor; A synchronous motor device comprising: a synchronization confirmation device that stops the supply of field current from the field control device to the synchronous motor when the parallel shunt switch is not closed within a certain time period even if the synchronization current is supplied. .