JPH02214430A - Protection of battery for cvcf power source - Google Patents

Abstract

PURPOSE:To separate a battery automatically from a load upon start of scheduled service interruption by switching from inverter power supply to bypass power supply, based on an inverter stop command, predetermined time before start of scheduled service interruption and switching from bypass power supply to inverter power supply, based on an operating command, predetermined time after finish of service interruption. CONSTITUTION:A control computor 6A transmits an inverter stop command for stopping an inverter 53 to a controller 59A, based on scheduled service interruption information being inputted, predetermined time before start of scheduled service interruption and carries out switching from inverter power supply through an inverter 53 to bypass power supply through a bypass switch 58. An inverter operational command for restarting the inverter 53 is transmitted to the controller 59A predetermined time after finish of scheduled service interruption thus carrying out switching from bypass power supply to inverter power supply. By such arrangement, a battery 54 can be released automatically from a load before scheduled service interruption is started and the battery can be connected automatically with the load after finish of scheduled service interruption.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for preventing capacity loss of a battery for a CVCF (constant voltage, constant frequency) power source, and in particular, relates to a method for automatically releasing battery load without increasing costs. The present invention also relates to a battery protection method for a CVCF power supply that performs connection.

[Prior Art] Generally, in a plant control system, a host computer and an operator who performs control input to the host computer are placed in a central monitoring room, and each control computer, which performs automatic control in an uncontrolled state, is placed in a central monitoring room. By placing it at the plant site and connecting the host computer and control computer with a transmission line, the plant status can be monitored from the central monitoring room.For example, in the case of a railway operation management system, it is possible to operate unattended. A control computer for station processing is placed at each station,
Status information from each control computer is displayed on a CRT in the central monitoring room.

In addition, a CVCF power supply that supplies high-quality constant voltage and constant frequency power is used as a power supply to drive the control computer, but the CVCF power supply includes an inverter for output conversion, a battery for power outage compensation, and a power supply in case of an abnormality. It has a built-in bypass switch, etc., and is particularly required to prevent battery life from deteriorating due to over-discharge.

Figure 4 shows, for example, "Electricity and Management" (March 1988 issue).
25 is a block diagram illustrating a plant control system using a conventional CVCF power source, which is described in the special feature "Techniques for utilizing rUPs" on pages 25 to 35.

In the figure, (1) is commercial power supply, (2) is commercial power supply (1
) is a private generator installed in parallel with (3), and (3) is a commercial power supply (
1) This is a power outage detection circuit that detects a power outage lasting longer than a certain period of time. (4a) and (4b) are changeover switches that are opened and closed complementary to each other by the changeover signal from the power failure detection circuit (3), and the normally open (a contact) changeover switch (4a) is connected to the private generator (2). The normally closed (b contact) changeover switch (4b) is connected to the output end of the commercial power source (1).

(5) is a C
It is a CF power supply, and the circuit breaker (
51) and a rectifier (52) connected to the circuit breaker (51)
and an inverter (
53), a battery (54) connected to the connection point of the rectifier (52) and the inverter (53), and the rectifier (52)
A circuit breaker inserted between the battery (54) and the battery (55)
, an isolation transformer (56) connected to the output end of the inverter (53), a normally closed (B contact) changeover switch (57) connected to the isolation transformer (56), and a rectifier (52).
) is connected in parallel between the input end of the changeover switch (57) and the output end of the changeover switch (57), and is composed of a bypass switch (58) that operates in conjunction with the changeover switch (57), and a microcomputer. ) and a controller (59) that controls opening and closing of the controller.

Although not particularly shown, the bypass switch (58) is a normally open (a contact) switch that operates complementary to the changeover switch (57), and connects the output of the inverter (53) and the output of the commercial power supply (1). and a thyristor circuit that synchronizes by eliminating the phase difference between the two. The controller (59) is C
Status information indicating the negative side and secondary side voltages of the VCF power supply (5), the operating status of the inverter (53), the charge/discharge status of the battery (54), etc. is monitored, and based on this status information, It outputs switching signals for the changeover switch (57) and bypass switch (58).

(6) is a control computer serving as a load for the CVCF power supply (5), and is installed at each of a plurality of plant sites (not shown) to be controlled. In addition, a control computer (6
) via any interface or communication line.
Connected to a controller (59) within the CFg source (5).

(7) is a host computer installed in a central monitoring room isolated from the plant site, and (8) is a transmission line for connecting the control computer (6) and host computer (7) to exchange signals. . (9) is a console connected to the host computer (7), and is equipped with a keyboard for input/output operations by an operator in the central monitoring room, and a CRT for displaying status information and the like.

The host computer (7) integrates multiple control computers (6) at each plant site, and is
It is driven by a power source separate from the control computer (6), and while the control computer (6) can be stopped depending on the situation at the plant site, it is continuously operated 24 hours a day under manned supervision.

Next, the operation of the conventional plant control system shown in FIG. 4 will be explained.

Normally, as shown in the figure, selector switches (4b), (5
7), circuit breakers (51) and (55) are closed;
The changeover switch (4a) and the bypass switch (58) are open, so the AC output from the commercial power supply (1) is converted to DC by the rectifier (52) in the CVCF power supply (5), and then converted to DC by the inverter (53). ) is converted into a constant voltage, constant frequency AC output by an isolation transformer (56).
It is supplied to the control computer (6) via.

In addition, the controller (
59) provides status information such as the input status of the negative side, the operating status of the inverter (53), the output status of the secondary side (pressure and frequency), the charge/discharge status of the battery (54), the status of various switches, the occurrence of abnormalities, etc. It is constantly output as information and is sent to the host computer (
7). These status information are displayed on the CR on the console (9) along with the operating status of the control computer (6).
This allows operators in the central monitoring room to know the operating status of the CVCF power supply (5) and control computer (6) for each plant site.

Based on the status information, the controller (59)
When determining an abnormality in the CVCFg source (5) or an overload condition on the control computer (6), the selector switch (57) is immediately opened and the bypass switch (58) is closed to form a bypass circuit. The AC output of the commercial power source (1) is directly supplied to the control computer (6). At this time,
The bypass circuit prevents instantaneous power supply interruption from the viewpoint of the control computer (6), and is designed to prevent power supply from being interrupted by the commercial power supply (1) and the inverter (
53) are formed so that no phase shift occurs between the respective output wave layers.

In addition, the battery (54), which is floatingly charged during normal operation of the CVCF power supply (5), is charged when the commercial power supply (1) has a power outage (Ill outage) and the output of the rectifier (52) is turned off. , drives the inverter (53) to continue supplying power to the control computer (6). At this time, the compensation time of the battery (54) is about 5 to 10 minutes, and the operation of the inverter (53) can be compensated for in the case of a normal instantaneous power outage, but in the case of a long-term planned power outage due to maintenance inspection, etc. This cannot be fully compensated for, and the battery (54) ends up being over-discharged.

Therefore, in order to protect the battery (54) during planned power outages, a private generator (2) is provided, and the commercial power source (1)
If a power outage continues for more than a certain period of time, the power outage detection circuit (
3) outputs a switching signal, opens the selector switch (4b) and disconnects the commercial power supply (1), and also opens the selector switch (4b).
4a) and connect the private generator (2) to the CVCFit source (
5).

As a result, the inverter (53) is driven via the rectifier (52), and the battery (54) is floating charged and protected from over-discharge. However, if the battery (54) is repeatedly charged and discharged every time a maintenance inspection is performed, the life of the battery (54) will be shortened, and the circuit breaker (51) may be damaged by the peak current including battery charging when power is restored. There is.

To prevent this, during maintenance and inspection, the operator manually opens circuit breakers (51) and (55), etc.
A method has also been implemented in which the inverter (53) is stopped to disconnect the battery (54) from the load.

[Problems to be Solved by the Invention] As described above, the conventional CVCF power supply battery protection method uses an expensive private generator (2) and a changeover switch (4a) to protect the battery (54) during planned power outages. , (4
Installing b) will increase the cost and will require a battery (
54), and when attempting to manually disconnect the battery (54) from the load, it requires a great deal of effort and is unreliable.

This invention was made to solve the above-mentioned problems, and provides a battery protection method for a CVCF power supply that can reliably and automatically disconnect the battery from the load during planned power outages without increasing costs. It is said that it is feathery.

[Means for Solving the Problems] In the CVCF power supply battery protection method according to the present invention, a control computer transmits an inverter stop command to a controller a certain time before the start of a planned power outage to switch from inverter power supply to bypass power supply. After a certain period of time from the end of the planned power outage, an inverter operation command is transmitted to the controller to switch from bypass power supply to inverter power supply.

[Operation] In the present invention, the battery is automatically released from the load before the planned power outage starts, and the battery is automatically connected to the load after the planned power outage ends.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
The figure is a block diagram showing a plant control system to which an embodiment of the present invention is applied, and in the figure, <5^),
(59A) and (6^) correspond to the CVCF power supply (5), controller (59), and control computer (6), respectively, and (1) and (7) to (9) are the same as above. It is something.

A is from the control computer (6^) to the controller (59A)
Control commands transmitted to, B is the controller (59A)
This is status information transmitted from to the control computer (6^). In this case, information is exchanged between the controller (59A) and the control computer (6^) using, for example, DI (digital input) and D
O (digital output), and the control computer (
6) and the controller (59) are connected by two contact signals consisting of an inverter stop command and an inverter operation command.

C is planned power outage information input by the operator;
The data is transmitted from the host computer (7) to the control computer (6^) via the transmission date m1 (8).

FIG. 2 is a timing chart showing time changes in inverter power supply and bypass power supply during planned power outages.
^l and ^2 are the inverter operation command and inverter stop command included in the control command A, B1 and B2 are the inverter operation status and bypass power supply status included in the status information B, τ is a certain period of time set to, for example, several seconds, T is the planned power outage duration over several hours.

FIG. 3 is a flowchart showing the operation of the control computer (6^) during a planned power outage. Steps 81 to S5 in FIG. 3(a) are the logic sequence at the start of a planned power outage, and FIG. 3(b) Steps 86 to S10 are a logic sequence at the end of a planned power outage.

Next, an embodiment of the present invention will be described with reference to FIGS. 1 to 3. Note that since the normal operation of the plant control system is the same as described above, only the battery protection operation will be described.

First, when the detailed schedule of planned power outages is clarified, an operator in the central monitoring room operates the console (9) and inputs planned power outage information C. This planned power outage information C is transmitted through the transmission line (8). input from the host computer (7) to the control computer (6^) via the control computer (6^).
).

In normal operation, the controller (59A) opens the changeover switch (57) in response to the inverter operation command ^I from the control computer (6^), and
^) is the state of inverter power supply. Further, the controller (59A>) transmits the inverter operation status log 1.

The control computer (6^) compares the planned power outage time in the planned power outage information C with the actual time, and monitors the planned power outage at the plant site (step S1).

That is, it is determined whether time t1, which is a certain period of time τ after the start of the planned power outage, has been reached (step S2), and if time 1. If the time has not been reached, the process returns to step S1, and when time t is reached, the inverter operation command ^1 is turned off and at the same time, the inverter stop command ^2 is transmitted (step S3).
.

This causes the controller (59A) to switch to the selector switch (
5)) is opened and the bypass switch (58) is closed, and the control computer (6^) is directly driven by the commercial power supply (1) via the bypass circuit. That is, at time t, a certain period of time τ before the start of the planned power outage, the inverter (53)
stops, bypass power supply is established, and the battery (54) is disconnected from the load and released. or.

In the status information B transmitted from the controller (59A), inverter operation status B1 is turned off and switched to bypass power supply status B2.

At this time, the control computer (6^) receives status information B.
In step S4), bypass power supply status B is monitored.
2 (step S5), and if it has not been switched, the process returns to step S4, and when it is determined that the switch has been made, the sequence before the planned power outage (Figure 2 (a) )) to end.

If a power outage actually occurs at the scheduled power outage start time t2, which is a fixed time interval τ after the time t1, power will not be supplied to the control computer (6^), so the bypass power supply status B2 will also be changed during the planned power outage time T. It turns off.

At this time, the control computer (6^) is the PIO.

The output state is latched and the output state is maintained even when the power is turned off.

When the planned power outage ends at time t, the commercial power supply (1
)'s output restarts the control computer (6^) and enters the bypass power supply state, but by turning on the power at this time,
The control computer (6^) automatically performs IPL (I n1ti).
Al Program Load) processing is performed (step S6).

Next, the control computer (6^) monitors the status information B (step S)) and actually controls the controller (59).
It is determined whether the bypass power supply status B2 is transmitted from A) and the inverter operation status B1 is off (step S8).

Then, when the bypass power supply status I12 is transmitted and it is determined that the inverter operation status B1 is off, the control computer (6^) determines that the controller The inverter operation command ^1 is transmitted to (59A), and the inverter stop command ^2 is turned off (step S
9), the sequence at the end of the planned power outage (FIG. 3(b)) is completed. As a result, the inverter (53) is restarted and returns to normal operation using inverter power supply, and the battery (54) is automatically connected to the load.

On the other hand, in step S8, the bypass power supply status B
If it is not confirmed that the old transmission and inverter operation status of 2 is OFF, the interface between the control computer (6^) and the controller (59A) or the controller (
59A) It is determined that there is an abnormality in itself, and abnormality processing is executed. Step 510) is abnormally terminated.

In this way, since the control computer (6^) automatically releases and connects the battery (54) to the load during a planned power outage based on the planned power outage information C, the private power generator as shown in Fig. 4 (2), selector switch (4a) and (
4b) becomes unnecessary, and there is no operational error and reliability is improved.

In the above embodiment, information was exchanged between the control computer (6^) and the controller (59A) using DI and Do using PIO contact signals. This may also be done by sending a message from the control computer (6^) to the controller (59A).
The message sent to the controller carries the control command A, and the controller (
Status information B will be included in the message from 59A) to the control computer (6^).

[Effects of the Invention] As described above, according to the present invention, the control computer transmits an inverter stop command to the controller a certain time before the start of the planned power outage to switch from inverter power supply to bypass power supply, and Since the inverter operation command is transmitted to the controller after a certain period of time to switch from bypass power supply to inverter power supply, battery protection for CVCF power supplies can be performed reliably and automatically to release and connect the battery to the load without increasing costs. There is an effect that can be obtained by the method.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing a blunt control system to which an embodiment of the present invention is applied, Fig. 2 is a timing chart diagram for explaining an embodiment of the invention, and Fig. 3 is an embodiment of the invention. A flowchart diagram to illustrate an example,
FIG. 4 is a block diagram showing a conventional plant control system. (1)...Commercial power supply (5^)...CVCF
Power supply (68)...Control computer (53)...Inverter (54)...Battery (58)...Bypass switch (59^)...Controller^1...Inverter operation command^ 2... Inverter stop command B1... Inverter operation status B2... Bypass power supply status C... Planned power outage information τ... Fixed time T...
Planned power outage time In the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] An inverter is inserted between a commercial power source and a control computer and converts the output of the commercial power source into a constant voltage and constant frequency; The battery in the CVCF power supply includes a battery that compensates for a power outage, a bypass switch connected in parallel to the inverter, and a controller that controls the bypass switch, and supplies constant voltage and constant frequency power to the control computer. In the protection method, the control computer transmits an inverter stop command to the controller to stop the inverter a certain time before the start of the planned power outage based on planned power outage information input in advance,
Switching from inverter power supply via the inverter to bypass power supply via the bypass switch, transmitting an inverter operation command to restart the inverter to the controller after a certain period of time after the end of the planned power outage, and restarting the bypass switch. Switching from power supply to the inverter power supply, automatically releasing the battery from the load a certain time before the start of the planned power outage, and automatically connecting the battery to the load a certain time after the end of the planned power outage. A CVCF power supply battery protection method characterized by: