JP2002291157A - Power supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide stabilizing power supply to a load even when the voltage of a bus bar 13 suddenly changes at the time of switching the power supply. SOLUTION: This power supply system comprises a variable frequency power supply device 2 for supplying power received from the bus bar 13 to a motor (load) 3 with prescribed frequency, a phase control device 4 for detecting the phase of the received power and controlling the variable frequency power supply device 2, a bus bar current detecting device 27 for detecting the current flowing from a bus bar 23 to the bus bar 13 at the time of switching the power, a monitor device 6 for stopping control of the variable frequency power supply device 2 by the phase control device 4 when signals from the bus bar current detecting device 27 are at and more than a preset value, and a signal switching device 5 which interlocks with power supply switching to input the signals from the bus bar current detecting device 27 to the monitor device 6. It is thus possible to restrain abnormal power from being supplied to the motor 3 when the voltage of the bus bar 13 becomes variable at the time of switching the power and suddenly changes due to the connection of a second system power supply 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply system having a frequency power supply device which prevents abnormal power such as overcurrent from being supplied to a load when a power supply system is switched in a redundant power supply system. .

[0002]

2. Description of the Related Art Conventionally, in a highly public facility such as a power generation plant, when an abnormality occurs in a power supply system, a method is adopted in which control is continued by disconnecting the power supply and switching to another power supply system. Have been.

FIG. 6 shows the configuration of such a power supply system. A first power supply 110 is provided as a normal power supply, and a second power supply 120 is provided as an emergency power supply.

The first system power supply 110 includes a transformer 111 for stepping down the voltage of the first system power supply 110,
, A secondary circuit breaker 112 provided on the secondary side, and a bus bar 113 connected by the secondary circuit breaker 112.

The first system power supply 110 includes a circuit breaker 101 connected to a bus 113, a static variable frequency power supply 102 connected to the bus 113 by the circuit breaker 101, and a static variable frequency power supply The motor 103 whose rotation speed is controlled by the output of the motor 102, a common-system phase detector 114 for detecting the voltage phase of the bus 113, and a phase for controlling the phase of the static variable frequency power supply 102 based on the output signal of the common-system phase detector 114 It has a control device 104 and the like.

Further, a circuit breaker 115 is connected to the bus 113, and an electric motor 116 such as an induction motor is connected as a load to the bus 113 via the circuit breaker 115.

On the other hand, the second system power supply 120 includes a transformer 121 for stepping down the voltage of the second system power supply 120, a secondary circuit breaker 122 provided on the secondary side of the transformer 121, And a bus 123 connected by the container 122.

When an abnormality occurs in the first system power supply 110, the electric power from the second system power supply 120 is
A bus breaker 130 connected to the bus 113 and the bus 123 is provided so as to be supplied to the motor 03 and the electric motor 116.

With such a configuration, the secondary circuit breaker 112 is normally turned on, and the busbar circuit breaker 130 is open.

In this normal state, the first system power supply 110
Therefore, when switching to the second system power supply 120, the secondary circuit breaker 112 is opened and the bus circuit breaker 130 is turned on sequentially, and the power of the second system power supply 120 is changed to the electric motor 103 or the electric motor. 116 and the like.

At this time, a state occurs where the secondary circuit breaker 112 is opened and the bus circuit breaker 130 is not turned on. That is, a state occurs in which only the load is connected to the bus 113.

In this state, for example, there is a case where the motor 116 of the induction motor continues to rotate due to the inertial force and acts as a generator. In such a case, the voltage, frequency, phase and the like of the bus 113 are controlled by the circuit breaker 115. It becomes the terminal voltage of the electric motor 116 connected via this.

Since this terminal voltage is determined by the energy stored in the motor 116, it decreases with time.

In such a state, when the bus breaker 130 is turned on and power is supplied from the bus 123,
Since the voltage, frequency, phase, and the like of the bus 113 change instantaneously to the voltage, frequency, phase, and the like of the bus 123, the voltage, frequency, phase, and the like of the bus 113 suddenly change.

However, even if the voltage, frequency, phase and the like of the bus 113 suddenly change, the phase control device 104 follows the response time of the proportional integration circuit constituting the phase control device 104 with a delay. The output of the motor 103 temporarily increases or decreases, and in some cases, an overcurrent or the like occurs, which causes an inconvenience that the motor 103 is affected by speed fluctuation or the like.

If the amount of change in the phase is very large, the proportional integration circuit becomes saturated, and the phase control device 104 may become inoperable, making it impossible to control the speed of the motor 103.

Further, depending on the phase control state at the time of power supply switching, the delay in following the phase control may exceed the range in which the phase control can be performed by the phase control device 104, resulting in a commutation failure. If the operation is performed in the mode (the mode in which the output from the rectifier is returned to the bus), a load short circuit occurs, which may cause a failure of the motor or the like.

Further, not only the phase but also the voltage value greatly changes transiently when the power supply is switched, so that in the static variable frequency power supply device, an overcurrent or the like may occur, which may cause a failure of the motor or the like.

In order to suppress such an inconvenience, a timer (not shown) is provided in the related art until a sudden change in the voltage, frequency, and phase thereof is settled (until a transient phenomenon is settled).
The control by the phase control device 104 is not performed.

[0020]

However, in a configuration in which a timer is provided so that control by the phase control device 104 is not performed until a transient phenomenon has settled, the set time of the timer is set in advance regardless of the situation. For this reason, the length of the motor 103 may be longer than necessary. In such a case, there may be a problem that the rotation speed of the electric motor 103 is significantly reduced.

Accordingly, an object of the present invention is to provide a power supply system capable of appropriately supplying power according to the situation even when power supply switching occurs.

[0022]

According to a first aspect of the present invention, there is provided a power supply system having a plurality of buses, at least one of which is a regular power supply system and the other is an emergency power supply system. A variable frequency power supply device that forms a power supply system, is connected to the bus of the service power supply system, and supplies power received through the bus to the load as power of a predetermined frequency, and a variable frequency power supply that detects the phase of the power to be received. A phase control device that controls the power supply device, a bus current detector that detects a current flowing from the bus on the emergency power supply side to the bus on the service power supply side during power supply switching, and a signal from the bus current detector.
At least when the value is larger than a preset value, the monitoring device stops the control of the variable frequency power supply device by the phase control device, and the signal from the bus current detector is input to the monitoring device in conjunction with the power supply switching operation. A signal switch is provided to suppress the supply of abnormal power to the load when the voltage or the like of the bus to which the load is connected fluctuates during power supply switching and this suddenly changes due to the connection of the emergency power supply. Features.

According to a second aspect of the present invention, there is provided a service power supply current detector for detecting a current flowing from the power supply in the service power supply system to the bus, and the signal switch switches power from the service power supply system to the emergency power supply system. When the power supply is switched, the signal from the bus current detector is input to the monitoring device in conjunction with the power supply switching operation.When the power supply is switched from the emergency power supply system to the service power supply system, the power supply switching operation is performed. Then, a signal from the normal power supply current detector is input to the monitoring device to suppress supply of abnormal power to the load even when the power is restored.

According to a third aspect of the present invention, the monitoring device stops the control of the variable frequency power supply device by the phase control device for a fixed time when the signal from the current detector is at least larger than a preset value. In this way, when the power supply is switched, the voltage of the bus to which the load is connected fluctuates, and when this suddenly changes due to the connection of the emergency power supply, the supply of abnormal power to the load is suppressed by a simple configuration. Features.

According to a fourth aspect of the present invention, there is provided a power supply system having a plurality of buses, at least one of which is a service power supply system and the other is an emergency power supply system, and is connected to a bus of the service power supply system. A variable frequency power supply that supplies the power received through the bus as power of a predetermined frequency to the load, a phase control device that detects the phase of the received power and controls the variable frequency power supply, A load-side current detector for detecting an inflowing current, and, when a signal from the load-side current detector is at least larger than a predetermined value, stopping control of the variable frequency power supply device by the phase control device. With a monitoring device,
With a small number of components, the voltage of the bus connected to the load fluctuates when the power supply is switched, and when the power suddenly changes due to the connection of the emergency power supply, the supply of abnormal power to the load is suppressed.

According to a fifth aspect of the present invention, there is provided a power supply system having a plurality of buses, at least one of which is a service power supply system and the other is an emergency power supply system, and is connected to the bus of the service power supply system. A variable frequency power supply for supplying power received through the bus as power of a predetermined frequency to a load; a phase control device for detecting the phase of the received power and controlling the variable frequency power supply; A system switching request signal is input, and a system switching monitoring device that stops the control of the variable frequency power supply device by the phase control device for a certain period of time is provided, so that abnormal power is not supplied to the load when necessary. It is characterized by.

According to a sixth aspect of the present invention, there is provided a power supply system having a plurality of buses, at least one of which is a service power supply system and the other is an emergency power supply system, and is connected to the bus of the service power supply system. A variable frequency power supply for supplying power received through the bus as power of a predetermined frequency to a load; a phase control device for detecting the phase of the received power to control the variable frequency power supply; A service phase detector for detecting a voltage phase of a bus in a power supply system, an emergency phase detector for detecting a voltage phase of a bus in the emergency power supply system, the service phase detector and the emergency phase detection A phase difference correction signal is output to the phase control device based on a signal from the device, and the phase difference control circuit controls the variable frequency power supply device based on the phase difference correction signal. The phase controller always controls the variable frequency power supply even when the voltage of the bus to which the load is connected fluctuates when the power supply is switched, and this suddenly changes due to the connection of the emergency power supply. However, the supply of abnormal power to the load is suppressed.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a power supply system having a redundant configuration according to the present embodiment. A first system power supply 10 (for example, a commercial power supply) connected to a bus 13 as a normal power supply, and a second power supply system connected to a bus 23 as an emergency power supply. A system power supply 20 (for example, a private power generation power supply) is provided.

In this embodiment, one emergency power supply is used.
However, the present invention is not limited to this, and can be applied to a case where a plurality is provided.

The first system power supply 10 is connected to the first system power supply 1.
A transformer 11 for stepping down a voltage of 0, the transformer 11 and the bus 1
3 and the like.

On the other hand, the second system power supply 20 has a transformer 21 for stepping down the voltage of the second system power supply 20, a power supply side circuit breaker 22 connected between the transformer 21 and the bus 23, and the like. ing.

A line connecting the bus 13 and the bus 23 is connected to a bus breaker 30 and is provided with a bus current detector 27 for detecting a current value flowing through the line.

The bus breaker 30 is provided with a signal switch 5 that operates in conjunction with the bus breaker 30.

One terminal of the signal switch 5 is connected to a monitoring device 6 described later, and the other terminal is connected to a bus current detector 27. When the bus breaker 30 is turned on, the signal from the bus current detector 27 is output. The signal is input to the monitoring device 6, performs a predetermined monitoring determination, and outputs a control signal to the phase control device 4.

The bus 13 is connected to a motor 16 such as an induction motor as a load via a load circuit breaker 15, and a phase as a load via the load circuit breaker 1 and the variable frequency power supply 2. An electric motor 3 such as a control motor is connected.

As a result, the electric motor 16 is rotated by the electric power from the bus 13, and the electric motor 3 is controlled by the variable frequency power supply 2 to rotate by the electric power from the bus 13.

A phase controller 4 is connected to the bus 13 via a service phase detector 14, and the voltage phase of the bus 13 is detected by the service phase detector 14, and phase control is performed based on the output signal. The device 4 controls the variable frequency power supply 2.

In such a configuration, when an abnormality occurs in the first system power supply 10 and the power supply is switched to the second system power supply 20, the power supply circuit breaker 12 is opened first, and then the bus circuit breaker 30 is operated. It is thrown.

When the bus breaker 30 is turned on, the signal switch 5 operates in conjunction with the bus breaker 30, and a signal from the bus current detector 27 is input to the monitoring device 6.

As described above, when the power supply is switched, the bus 1
3 is connected only to the motor 16 or the like, and its voltage, frequency, phase, and the like fluctuate, and from this state, the voltage, frequency, phase, and the like of the bus 23 are instantaneously switched.

Accordingly, the detection signal of the service phase detector 14 also changes suddenly, and the phase controller 4 attempts to control the variable frequency power supply 2 based on the detection signal.

At this time, the various inconveniences described above occur due to the delay of the response time of the proportional integration circuit constituting the phase control device 4.

Therefore, in the present embodiment, the value of the current flowing from the bus 23 to the bus 13 is detected by the bus current detector 27, and the monitoring result is monitored by the monitoring device 6.

The monitoring device 6 controls the phase control off signal when the detected current value is equal to or greater than a preset value, and the phase control on signal when the detected current value is less than the preset value. Output to the device 4.

The phase control device 4 is used only when the phase control ON signal is received from the monitoring device 6.
The control of the variable frequency power supply 2 based on the detection signal from the control unit 4 is performed, and when the phase control off signal is received, the control is stopped.

It should be noted that the current value preset in the monitoring device 6 can alleviate sudden fluctuations in the voltage and phase of the bus 13 at the time of power supply switching, so that at least the phase control device 4 can perform normal control operations. It can be defined as a current value.

Therefore, the influence of the input overcurrent of the motor 3 can be minimized, and the speed fluctuation can be suppressed, and the reliability is improved.

In the above description, the case where the power supply is switched from the first power supply 10 to the second power supply 20 has been described. However, when the first power supply 10 is restored, the first power supply 20 is switched to the first power supply. The power supply is switched to the system power supply 10,
In this case, a similar problem occurs.

In such a case, as shown in FIG.
The signal switch 5 is configured to operate in conjunction with the power supply circuit breaker 12, and the power supply circuit breaker 12 and the transformer 11
It is possible to cope with this by providing the ordinary power supply current detector 17 on the line connecting the two and performing the operation opposite to the operation described above.

That is, when the first system power supply 10 which is a normal power supply is restored, the power supply side circuit breaker 22 and the bus circuit breaker 3
Since 0 is released, the voltage, frequency, phase, and the like of the bus 13 fluctuate. Thereafter, the power supply circuit breaker 12 is turned on, and power is supplied from the first system power supply 10 to the electric motor 3 and the like via the bus 13.

At this time, the voltage, frequency, phase, and the like of the bus 13 are instantaneously switched to the voltage, frequency, phase, and the like of the first system power supply 10, which causes a problem that the phase control device 4 cannot operate normally.

Therefore, when the power supply circuit breaker 12 is turned on, the signal switch 5 switches the signal path so that the signal from the service power supply current detector 17 is input to the monitoring device 6 in conjunction with this.

Thus, the monitoring device 6 outputs the phase control off signal when the current value from the ordinary power supply current detector 17 is equal to or more than a preset value, and outputs the phase control off signal when the current value is less than the preset value. The control ON signal is output to the phase control device 4 to minimize the influence of the input overcurrent of the electric motor 3 and the like, thereby suppressing the speed fluctuation and thereby improving the reliability.

By the way, in the above description, the monitoring device 6
Is a phase control off signal when the current value from the service power supply current detector 17 and the bus current detector 27 is equal to or greater than a preset value, and a phase control on signal when the current value is less than the preset value. Is output to the phase control device 4,
The present invention is not limited to this. For example, when the current values from the normal power supply current detector 17 and the bus current detector 27 become equal to or greater than a preset value, the phase control off signal is output for a fixed time. You may.

With such a configuration, the phase control off signal may continue to be output more than necessary in some cases. However, at least a timer is provided as in the related art, and the phase controller There is an advantage that finer control can be performed as compared with the case where the control is stopped.

The monitoring device 6 has been described on the premise that the monitoring is performed based on the current value. However, the monitoring device 6 can be appropriately set according to the conditions such as the voltage, phase, and frequency. It is included in.

Next, a second embodiment of the present invention will be described with reference to the drawings. Note that the same components as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

In the above-described first embodiment, in order to suppress inconvenience such that the phase control device 4 does not operate normally due to sudden changes in the voltage, frequency, phase and the like of the buses 13 and 23 at the time of power supply switching. From bus 23 to bus 13
Also, a current flowing from the first system power supply 10 to the bus 13 from the power supply side to the bus 13 is detected, and based on the detection signal, the monitoring device 6
Was controlled.

On the other hand, in the present embodiment, the motor 3
The monitoring device 6 detects the current flowing between the load and the bus 13 and the like, and the monitoring device 6
Is performed.

With such a configuration, the first system power supply 1
Even when switching from 0 to the second system power supply 20 and from the second system power supply 20 to the first system power supply 10 are performed,
The number of the current detectors may be one, and the number of the current detectors may be one even when a plurality of emergency power supplies are provided. Therefore, cost reduction and improvement in reliability can be achieved by reducing the number of members.

That is, as shown in FIG. 3, a load-side current detector 7 is provided on a line connecting the load-side circuit breaker 1 on the load side and the variable frequency power supply device 2. The monitoring device 6 controls the phase control device 4 based on the signal.

Thus, the monitoring device 6 outputs the phase control off signal when the current value from the load-side current detector 7 is equal to or greater than a preset value, and outputs the phase control off signal when the current value is less than the preset value. By outputting a control-on signal to the phase control device 4 to minimize the influence of the input overcurrent of the electric motor 3 and the like, and suppress the speed fluctuation, the reliability is improved.

In this case, when the current value from the load-side current detector 7 exceeds a preset value, the phase control off signal may be output for a fixed time.

In such a configuration, the phase control off signal may continue to be output more than necessary in some cases. However, at least a timer is provided as in the conventional case and the phase control device There is an advantage that finer control can be performed as compared with the case where the control is stopped.

Next, a third embodiment of the present invention will be described with reference to the drawings. Note that the same components as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

In the second embodiment, the current and the like flowing between the load such as the motor 3 and the bus 13 are detected, and the variable frequency power supply 2
Was not controlled.

On the other hand, in this embodiment, as shown in FIG. 4, a system switching monitoring device is provided to control the phase control device 4 based on a system switching request signal.

That is, when the power is switched, a system switching request signal to that effect is input to the system switching monitoring device 8. As a result, the system switching monitoring device 8 outputs a phase control off signal to the phase control device 4 only for a certain period of time to suppress the influence of the input overcurrent of the electric motor 3 and to minimize the speed fluctuation. I have.

Next, a fourth embodiment of the present invention will be described with reference to the drawings. Note that the same components as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

In each of the embodiments described above, when the phase control device 4 receives the phase control off signal, the control of the variable frequency power supply device 2 is stopped. That is, there is a time zone in which the control of the phase control device 4 is stopped.

On the other hand, in the present embodiment, the phase control device 4 always operates normally while preventing the occurrence of such a time zone.

That is, as shown in FIG.
The phase difference correction means 9 for correcting the signal output from the controller 23 and the emergency system phase detector 24 for detecting the voltage phase of the bus 23 are provided, and the service system phase detector 14 and the emergency system phase detector 24 are provided. The phase difference correction means 9 corrects the control signal output from the phase control device 4 based on the signals.

Thus, even if the voltage or phase of the bus 13 changes suddenly, for example, the phase control device 4 immediately calculates the control signal based only on the signal from the service phase detector 14 and executes the control signal. Is controlled, and the ordinary system phase detector 14 is controlled based on the correction signal from the phase difference correcting means 9.
And controls the variable frequency power supply 2 by calculating a control signal or the like based on the corrected signal.

Since the correction signal at this time is a content that prevents the phase control device 4 from saturating or from being unable to operate normally, the phase control device 4 always operates normally and controls the variable frequency power supply 2. As a result, the input of an overcurrent to the electric motor 3 can be suppressed, and the speed fluctuation can be minimized.

[0075]

As described above, according to the present invention,
A sudden change due to the voltage, frequency, phase, etc. of the bus connected to the load that occurs at the time of power supply switching is monitored by the monitoring device, and the phase control device always operates normally, enabling highly reliable power supply. Become.

[Brief description of the drawings]

FIG. 1 is a power supply system diagram applied to the description of a first embodiment of the present invention.

FIG. 2 is applied to the description of the first embodiment of the present invention,
FIG. 4 is a power supply system diagram that can cope with power recovery.

FIG. 3 is a power supply system diagram applied to the description of a second embodiment of the present invention.

FIG. 4 is a power supply system diagram applied to the description of a third embodiment of the present invention.

FIG. 5 is a power supply system diagram applied to the description of a fourth embodiment of the present invention.

FIG. 6 is a power supply system diagram applied to the description of the conventional technique.

[Explanation of symbols]

 Reference Signs List 2 variable frequency power supply device 3, 16 motor 4 phase control device 5 signal switch 6 monitoring device 7 load side current detector 8 system switching monitoring device 9 phase difference correcting means 10 first system power supply 12, 22 power supply circuit breaker 13, Reference Signs List 23 bus 14 service phase detector 17 service current detector 20 second power supply 24 emergency phase detector 27 bus current detector 30 bus breaker

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shinji Hirota 66-2 Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa F-term within Toshiba Engineering Corporation (reference) 5G066 AA20 AB10 AD20 AE11

Claims (6)

[Claims] A power supply system having a plurality of buses is provided, at least one of which is a service power supply system and the other is an emergency power supply system. The power supply system is connected to a bus of the service power supply system via the bus. A variable frequency power supply that supplies received power to a load as power of a predetermined frequency; a phase control device that detects the phase of the received power to control the variable frequency power supply; A bus current detector for detecting a current flowing from the bus on the side to the bus on the service power supply side, and when a signal from the bus current detector is at least larger than a predetermined value, the phase control device A monitoring device for stopping control of the variable frequency power supply device, and a signal switch for inputting a signal from the bus current detector to the monitoring device in conjunction with a power supply switching operation. Power supply system, characterized in that the. 2. A power supply current detector for detecting a current flowing from a power supply in the service power supply system to a bus, and wherein the signal switch switches power from the service power supply system to the emergency power supply system. In conjunction with the power supply switching operation, the signal from the bus current detector is input to the monitoring device, and when performing power supply switching from the emergency power supply system to the regular power supply system, the power supply switching operation is interlocked. The power supply system according to claim 1, wherein a signal from the service power supply current detector is input to the monitoring device. 3. The monitoring device according to claim 1, wherein the control unit stops the control of the variable frequency power supply device by the phase control device for a fixed time when the signal from the current detector is at least greater than a preset value. 3. The power supply system according to claim 1, wherein: 4. A power supply system having a plurality of buses is provided, at least one of which is a service power supply system and the other is an emergency power supply system. The power supply system is connected to the bus of the service power supply system via the buses. A variable frequency power supply that supplies received power to a load as power of a predetermined frequency; a phase control device that detects a phase of the received power to control the variable frequency power supply; and a load that detects a current flowing into the load. A side current detector; and a monitoring device that stops control of the variable frequency power supply device by the phase control device when a signal from the load side current detector is at least larger than a preset value. A power supply system characterized by: 5. A power supply system having a plurality of buses is provided, at least one of which is a service power supply system and the other is an emergency power supply system. The power supply system is connected to the bus of the service power supply system via the bus. A variable frequency power supply that supplies the received power to the load as power of a predetermined frequency; a phase control device that detects the phase of the received power and controls the variable frequency power supply; And a system switching monitoring device for inputting and stopping control of the variable frequency power supply device by the phase control device for a fixed time. 6. A power supply system having a plurality of buses is provided, at least one of which is a service power supply system and the other is an emergency power supply system. The power supply system is connected to the bus of the service power supply system via the buses. A variable frequency power supply that supplies the received power to the load as power of a predetermined frequency; a phase control device that detects the phase of the received power to control the variable frequency power supply; and a bus voltage in the service power system. A system phase detector for detecting a phase, an emergency system phase detector for detecting a voltage phase of a bus in the emergency power supply system, and a signal from the service system phase detector and the emergency system phase detector. Outputting a phase difference correction signal to the phase control device, and causing the phase difference control circuit to control the variable frequency power supply device based on the phase difference correction signal. Power supply system, wherein the stage, in that it comprises.