JPH07101975B2 - Auxiliary machine automatic operation switching method - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for automatically switching an auxiliary machine of a liquefied gas fuel base.

[Technical background of the invention and its problems] With the increase in capacity of power generation units in recent years, and reflecting the global energy situation, liquefied gas has come to be used as fuel for power generation units. It was As a large-scale one has been constructed as the receiving terminal, the number of cases where the receiving terminal itself vaporizes and supplies it directly to the power generation plant is increasing. Therefore, the trouble at the receiving terminal side also leads to the shutdown of the power generation plant, and particularly high reliability is required in operating the terminal.

In order to meet this requirement, the liquefied gas fuel base's on-site power source configuration generally adopts a two-system power receiving system consisting of two systems. In the event of an accident in one system or a power failure without warning. In this case, the power supply is switched automatically and in a short time only by disconnecting the power supply on the fault side and turning on the busbar breaker. However, in the case of a one-line ground fault in the content of the accident, the bus bar switching cannot be performed because the ground fault point by the detection device and the influence range due to the ground fault are not clear. Therefore, if the operator is notified as a ground fault alarm and the ground fault does not recover within a certain period of time, the operator has the same type of auxiliary equipment as one of the healthy side auxiliary equipment, that is, the auxiliary equipment of the ground fault side system. It is usual to carry out an operation movement operation of an auxiliary machine that starts the machine and stops the auxiliary machine operating the system on the ground fault side.

However, this operation leaves the operator with a predictive judgment of the possibility of moving from the one-line ground fault to the two-phase short circuit, and in the situation where it is not known when to shift to the two-phase short circuit,
Since the operation movement operation of the auxiliary equipment is performed, there is a risk of causing a power failure of the power supply system on the ground fault side and an erroneous operation of the operator.

[Object of the Invention] The present invention automatically switches from a ground fault system to a sound system auxiliary machine at the time of a one-line ground fault accident, and at that time, depending on the importance of the auxiliary machine, the ground fault system and the sound system auxiliary machine are supplemented. Automatic operation switching method for auxiliary machine to automatically start and stop machine [Outline of the invention] Therefore, the start signal is issued to the auxiliary machine of the same kind as the ground fault system operation auxiliary machine by the one-line ground fault accident detection element and the timer element. , A circuit is configured to automatically start in the order of importance of the predetermined auxiliary equipment so as not to exceed the overload withstanding capacity of the transformer due to the inrush current caused by the auxiliary equipment start-up. , Stop the operation auxiliary equipment of the ground fault system at any time,
This is to enable the plant to continue stable and safe operation.

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

FIG. 1 shows the internal power supply configuration of the liquefied gas fuel base. The power supply 1 is fed from the common bus 2 to the A system bus 6 via the A system common bus breaker 3, the A system transformer 4, and the A system power breaker 5. Importance 1 rank auxiliary machine 11
A is started / stopped by opening / closing the priority level 1 auxiliary machine breaker 111A. Auxiliary motor and cable ground fault
It is detected by the feeder ground fault detectors 14A1, 14A2, 14A3 and output to the alarm device. The second-rank importance equipment 12A is started and stopped by opening and closing the second-rank importance equipment breaker 112A. The 3rd-rank importance auxiliary equipment 13A is started and stopped by opening / closing the 3rd-rank importance auxiliary circuit breaker 113A.

Similarly, the power supply 1 is also supplied from the common bus 2 to the B system bus 10 via the B system common bus breaker 7, the B system transformer 8, and the B system power receiving breaker 9. The priority 1 rank accessory 11B is started and stopped by opening and closing the importance 1 rank accessory breaker 111B. Auxiliary motor and cable ground fault
It is detected by the feeder ground fault detectors 14B1, 14B2, 14B3 and output to the alarm device. The second-rank importance equipment 12B is started and stopped by opening and closing the second-rank importance equipment breaker 112B. The importance rank 3 rank auxiliary machine 13B is started and stopped by opening and closing the importance rank auxiliary machine breaker 113B.

The detection signals from the feeder ground fault detectors 14A1 to 3 and 14B1 to 3, transformer secondary side ground fault detectors 15A and 15B, and bus bar ground fault detectors 16A and 16B are taken into the automatic operation switching device 20 and processed. , As a result, the auxiliary circuit breaker 111A, 111B, 112A, 112B, 113A, 113
B open / close control is performed. In the figure, 52BT indicates a busbar breaker.

As described above, the same type of auxiliary equipment is installed in the A and B systems, and normally the A and B systems are operated in a balanced manner.

FIG. 2 is a flow chart showing the operation of the automatic operation switching device 20 by taking as an example the occurrence of a ground fault in the A side power supply system of FIG.

The operation determination step (21) of the transformer secondary side ground fault detection device 15A in the A transformer neutral point grounding circuit is independently alerted and notified to the operator. If YES in the step (22) of judging whether or not the A-system power breaker 5 is ON, the feeder ground fault detectors 14A1, 14A2, in FIG.
14A3 operation Feeder Ground fault judgment step (23)
Proceed to. On the other hand, the operation of the busbar ground fault detection device 16A, that is, A
The determination step (24) for determining whether or not there is a system bus single line ground fault also proceeds to the determination step (23) for determining whether or not there is a feeder ground fault. When it is not a feeder ground fault, that is, it is not a ground fault for each auxiliary machine but a secondary side ground fault or A of the A-system transformer 4 that affects the entire auxiliary machine.
A timer (2
5) is started, and by the output of the timer counter UP judgment step (26), the starting operation (27) of the B system importance 1 rank auxiliary machine 11B is performed. Next, in the start determination step (28), the start is confirmed, and the B system importance 2 rank auxiliary machine 12B start operation (3
At the same time as 0), the operation (29) of stopping the auxiliary equipment 11A of importance 1 rank of the A system is performed. B system importance 2 rank auxiliary machine 12
The startup is confirmed in the startup determination step (31) of the startup operation (30) of B, and a signal is sent to the startup operation of the auxiliary equipment of the next importance rank, and as in the previous step, the A-rank importance 2 rank auxiliary equipment 12A
Stop operation (32). Except when the ground fault is detected in this way and the timer is restored within a certain time by the timer under some condition, the timer count map is performed, so that the auxiliary equipment is ordered in a predetermined order of the importance rank of the sound system. At the same time as starting up, stop the ground-fault auxiliary equipment that became unnecessary. By repeating such steps, the automatic operation switching operation of the auxiliary machine can be performed.

At this time, the operation of any one of the feeder ground fault detectors 14A1, 14A2, and 14A3, that is, the ground fault determination step (33) for each auxiliary device,
(34) By issuing a start signal to the sound B-system auxiliary equipment of the same rank, the automatic operation switching operation of the auxiliary equipment can be performed even when the feeder has a single ground fault.

It should be noted that the ranking of importance is determined by the scale of each plant and the capacity of the power transformer, and it is possible to include a plurality of auxiliary machines in the same rank depending on the capacity of the power transformer.

Further, it goes without saying that the interlock in the starting operation of the auxiliary equipment is a comprehensive starting interlock by combining various conditions in the operation, and various alarm signals may be generated to notify the operator there. It is possible within the scope of the prior art.

Although the flowchart of FIG. 2 can be realized by using hard wiring, it can be easily realized by using a microcomputer, which has made remarkable progress recently, and can be incorporated into plant control in a computer.

Further, in the above embodiment, the case where the ground fault occurs on the system A side has been described, but it goes without saying that the same can be performed when the ground fault occurs on the system B side.

[Effects of the Invention] As described above, according to the present invention, it is possible to omit the operation determination at the time of occurrence of the ground fault, which is most difficult for conventional operators, and automatically perform the operation switching operation of complicated auxiliary equipment in a short time. It is possible to prevent operator's erroneous operation, and at the same time, the auxiliary equipment required for inspection of the power supply system for ground fault occurrence is stopped at the same time, so the safe operation of the process system of the liquefied gas fuel base consisting of two systems and the on-site It can greatly contribute to securing a power source.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an on-site power source of a liquefied gas fuel base according to an embodiment of the present invention, and FIG. 2 is a flowchart of the present invention showing an operation when a ground fault occurs in the A system of FIG. 1 ... Power supply, 2 ... Common busbar, 3 ... A system common bus breaker, 4 ... A system transformer, 5 ... A system power receiving breaker, 6 ... A system busbar, 7 ... B system Common bus breaker, 8 ... B system transformer, 9 ... B system power breaker,
10 …… B system bus.

Claims (1)

[Claims] 1. An automatic operation switching method for an auxiliary machine, which switches operating states of a plurality of auxiliary machines respectively connected to a central bus of an A, B2 system that receives power from a power supply system via two transformers, respectively. An operation determination step 1 for determining the operation of the A system transformer ground fault detection device provided on the secondary side of the A system transformer, and when an operation is detected in the operation determination step 1,
The operation judging step 2 for detecting the operation of the A-system breaker provided between the secondary side of the A-system transformer and the in-house busbar, and the operation judging step 2 when the non-operation is detected in the operation judging step 1. The operation determination step 3 which detects the operation of the system A bus ground fault detector that detects the ground fault of the in-house bus, and returns to the operation determination step 1 when the inactivity is detected, the operation determination step 2, and the operation determination step 2, When an operation is detected in the operation determination step 3, an operation determination step 4 of detecting an operation of the A-system feeder ground fault detector provided according to the A-system auxiliary machine, and the operation determination step When a malfunction is detected, a start-up operation step of performing a start-up operation from an auxiliary machine having a high degree of importance among the plurality of auxiliary machines provided in the B-system, and the auxiliary operation of the B-system at the start-up operation step Machine startup operation If it is confirmed, the automatic operation switching method for an auxiliary machine comprises a start / stop step of starting / stopping the auxiliary machine having a high degree of importance among a plurality of auxiliary machines provided in the A system.