JPH1075534A - Device for detecting abnormality of commercial synchronizing cvcf power supplies in parallel operation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to detect abnormalities either when a CVCF power supply operates by internal synchronization in spite of a state that the entire system must operate by an external synchronizing command or, on the contrary, when a CVCF power supply operates by external synchronization in spite of a state that the entire system must operate by an internal synchronizing command, in CVCF power supplies operated in parallel. SOLUTION: By providing a circuit for detecting the abnormality of its own unit, each CVCF power supply makes it possible to parallel itself off (by giving a self- parallel-off command 15 to itself) when any one of the CVCF power supplies is in a state that an external synchronizing command is inputted (i.e., the synchronizing command state 13 of the entire system is in the external synchronizing command) and that the CVCF power supply itself is in a state of operation corresponding to an internal synchronizing command or that the CVCF power supplies are all in a state that an internal synchronizing command is inputted (i.e., the synchronizing command state 13 of the entire system is in the internal synchronizing command) and that each CVCF power supply itself is in a state of operation corresponding to an external synchronizing command lasts for a specified time TO.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects an abnormal power supply in a CVCF inverter power supply (hereinafter abbreviated as CVCF power supply or simply CVCF) which is operated in parallel with a commercial power supply at all times and detects the abnormal power supply. The present invention relates to a parallel commercial synchronous type CVCF power supply abnormality detection device for disconnecting from operation.

[0002] In the drawings, the same reference numerals indicate the same or corresponding parts.

[0003]

2. Description of the Related Art FIG. 2 is a single-line diagram of a parallel commercial synchronous CVCF. In the figure, 3 is a commercial power supply, and 1 (1-
Nos. 1 to 1-n) are No. No. 1 to No. n of the CVCFs 6 that are operated in parallel,
The load can be fed from any of the power supplies 1. 1a (1a
1 to lan) are breakers of a motor drive for supplying each of the CVCFs 1-1 to 1-n to the load 6, 5 is a thyristor switch for supplying the commercial power supply 3 to the load 6 at high speed, and 4 is a thyristor switch 5. Is a motor drive breaker (referred to as a direct feed breaker) for continuously connecting the commercial power supply 3 to the load 6 after the power supply is turned on.

No. is usually used. l of CVCF1-l to N
o. breakers 1al to lan up to n CVCF1-n
The CVCF power supplies 1-1 to 1-n synchronize with the commercial power supply 3 and supply power to the load 6 while performing parallel operation. At this time, the direct feed breaker 4 and the thyristor switch 5 are in the OFF state. Next, in the unlikely event that a failure occurs in the CVCF 1 in parallel operation and it becomes impossible to supply power to the load 6, only the CVCF 1 in which the failure has occurred is once disconnected from the parallel operation, and further separated by this disconnection. C left
If VCF1 is overloaded, CVC during parallel operation
The thyristor switch 5 and the direct feed breaker 5 are turned on under the condition that all the commercial power sources 3 of F1 are synchronized.
Then, all the breakers 1a are turned off, the power supply to the load 6 is switched from the CVCF power supply 1 side to the commercial power supply 3 side, and the power supply to the load 6 is continued.

As described above, each CVCF power supply 1-
The operation of synchronizing the outputs 1 to 1-n with the commercial power supply 3 (i.e., matching the frequency and the phase) is called external synchronization. On the other hand, the output of the CVCF 1 is controlled by the CVCF 1 independently of the commercial power supply 3. Operating at a common frequency set in advance for each CVCF 1 using a crystal oscillator provided therein is called internal synchronization. However, also at the time of this internal synchronization, each CVCF 1 in parallel operation performs control to synchronize with the other CVCFs 1 in phase with each other. In addition,
In FIG. 2, reference numeral 7 denotes an output bus panel provided with means for controlling connection of the CVCF power supply 1 or the commercial power supply 3 to the load 6 and the like.

[0006]

By the way, in a CVCF operating in parallel, when a certain CVCF operates in internal synchronization even though the entire system is in a state to operate according to an external synchronization command, or conversely, the system When a certain CVCF is operated in external synchronization even though the whole is in a state to operate in accordance with the internal synchronization command, a phase difference occurs between the CVCFs in parallel operation, and a cross current flows,
There is a problem that the CVCF is stopped including the CVCF having no abnormality.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a parallel commercial synchronous type CVCF power supply abnormality detecting apparatus which can eliminate this problem.

[0008]

In order to solve such a problem, an abnormality detecting device according to the present invention comprises a plurality of CVs.
A CF power source (eg, 1), wherein each of the CVCF power sources is
Based on the internal synchronization command (via its own crystal oscillator, etc.), it performs parallel operation with a preset common frequency and synchronizes phases with each other. In the parallel commercial synchronous type CVCF power supply which performs the parallel operation of the CVCF power supplies by making the frequency and phase coincide with the power supply (such as 3),
Any one of the CVCF power supplies is in an input state of the external synchronization command (that is, the synchronization command state 13 of the entire system is an external synchronization command state), and the CF power supply is in an operation state corresponding to the internal synchronization command. Or the CVC
When all the F power supplies are in the input state of the internal synchronization command (that is, the synchronization command state 13 of the entire system is the internal synchronization command state) and are in the operation state corresponding to the external synchronization command, the power supply for a predetermined time ( If the confirmation time period T0 is continued, the means for disconnecting itself from the parallel operation (by giving the own equipment disconnection command 15 etc.) (self equipment abnormality detection circuit)
10).

According to the present invention, when an inconsistency between the input state of the synchronization command to the entire system and its own operation state continues for a predetermined time, each CVCF power supply detects its own unit abnormality which disconnects itself from the parallel operation. A circuit was provided.

[0010]

Next, embodiments of the present invention will be described with reference to the drawings. In the following, for convenience, it is assumed that the number of CVCFs 1 in FIG. 2 is two, 1-1 and 1-n. FIG. 1 is a configuration diagram of a main circuit according to an embodiment of the present invention. FIG. 1 shows an example of a configuration of a circuit 10 for detecting an abnormality of a self-device incorporated in each of the CVCFs 1-1 to 1-n in FIG. Show. FIG.
In the figure, reference numeral 11 denotes a signal indicating the state of the synchronization command input to the CVCF 1 of the own device, which is H when in the external synchronization command state and L when in the internal synchronization command state. Reference numeral 12 denotes a signal indicating the synchronization command state input to the CVCF 1 of the other unit, which is H when in the external synchronization command state and L when in the internal synchronization state. Reference numeral 14 denotes a signal indicating whether the actual operation state of the own machine is the operation state (H) corresponding to the external synchronization command, but is the operation state (L) corresponding to the internal synchronization command.
Here, <own machine is No. in FIG. In the case of CVCF1-1, the other device synchronization command state 12 in FIG. nCV
All other signals received from CF1-n in FIG. 1CVCF1-l (own device). Also, the own machine is No. 2 in FIG. In the case of nCVCF1-n, the above is reversed.

In FIG. 1, in order to know the state 13 of the synchronization command of the whole system, the synchronization command
The OR condition of 11 and the synchronization command status 12 of another
Determined by 11. Next, the EXOR circuit G12 determines a mismatch between the synchronization command state 13 of the entire system obtained under the OR condition and the synchronization operation state 14 of the own device, and if they do not match (that is, if the output of the EXOR circuit G12 is H). After the confirmation time T0, the control unit issues the own unit disconnection command 15 to disconnect the CVCF power supply 1 of the own unit (own unit) from the parallel operation.

[0012]

According to the present invention, each CVC operating in parallel
The F power supply itself detects that it has moved differently from the synchronization command of the entire system, and includes means for disconnecting itself from the parallel operation. Therefore, based on the cross current caused by the generation of the abnormal CVCF power supply, a sound CVCF Can be prevented with a cheap configuration.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a main part configuration as an embodiment of the present invention.

FIG. 2 is a single-line diagram showing a system configuration of a conventional parallel commercial synchronous CVCF power supply.

[Explanation of symbols]

 1, 1-l to 1-n CVCF power supply 3 Commercial power supply 6 Load 7 Output bus board 10 Own unit abnormality detection circuit 11 Own unit synchronization command state 12 Other unit synchronization instruction state, 13 Synchronization command state of whole system 14 Own unit synchronization Operation status 15 Own unit disconnection command

Claims (1)

[Claims] A plurality of CVCF power supplies;
Based on the internal synchronization command, the CF power supply performs parallel operation with a preset common frequency and synchronizes the phases with each other to perform parallel operation. On the other hand, the CF power supply matches the frequency and phase with the commercial power supply based on the external synchronization command. In the parallel commercial synchronous CVCF power supply that performs parallel operation among the CVCF power supplies, each of the CVCF power supplies is in a state where any one of the CVCF power supplies is in the input state of the external synchronization command and is itself the internal synchronization command. If the CVCF power supply is in the input state of the internal synchronization command and is itself in the operation state corresponding to the external synchronization command, when the CVCF power supply is in the operation state corresponding to An apparatus for detecting abnormality of a parallel commercial synchronous CVCF power supply, comprising: means for disconnecting itself from the parallel operation.