JPH01295626A - Power unit for peak load - Google Patents

Abstract

PURPOSE:To reduce energy loss and to realize highly efficient operation by feeding power selectively from a motor during an interval when power consumption is lower then a set value while feeding power selectively from an engine when power consumption exceeds over the value. CONSTITUTION:When a motor 3 starts operation, a power consumption detector 16 detects power consumption and the motor 3 is operated continuously if the power consumption is lower a set value. If power consumption exceeds over the set value during operation of the motor 3, a selection controller 7 switches operation from the motor 3 to an engine 5, and the engine 5 is operated continuously so long as power consumption is higher then the set value. If power consumption drops below the set value during operation of the motor 3, the selection controller 7 switches operation from the engine 5 to the motor 3 and the motor 3 operates continuously so long as power consumption is lower than the set value.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION This invention relates to a peak load countermeasure power device for driving pumps, compressors, etc.

Prior Art and Problems of the Invention Generally, as a power source for driving pumps, compressors, etc.
Electric motors are used.

By the way, there is a large difference in the amount of electricity used during the day and at night, and the peak value of electricity used during the day (beeping load) may become abnormally large, so countermeasures are required.

As countermeasures against peak power loads, methods have been adopted such as stopping part of the load and supplementing power by generating electricity using in-house power generation equipment. However, the former is not a fundamental solution. In the latter case, a generator is connected to the prime mover to convert the output of the prime mover into electric power, but losses occur at each stage of power generation, substation, power transmission, and motor. For example, in the case of a diesel engine, the capacity of the generator attached to the prime mover is 79 to 94 when the prime mover output is 100. In addition, since the latter method involves parallel operation with a commercial power source, protection and monitoring equipment necessary for parallel operation is required, and legal handling is also limited.
They are classified as "power plants" and are subject to various handling regulations.

An object of the present invention is to provide a peak load countermeasure power plant that solves all of the above problems.

Means for Solving the Problems A power plant according to the present invention detects the electric motor and prime mover connected to the load, as well as the power used by the power system, and selects the power from the electric motor to the load while the used power is below a set value. The motor is equipped with a selection control means for selectively supplying power from the prime mover to the load when the power used exceeds a set value.

Since power from the prime mover is selectively supplied to the load when the power used in the operating power system exceeds a set value, it is possible to suppress the peak load and prevent the power used from becoming abnormally large.

Since the power of the prime mover is directly supplied to the load, energy loss is reduced and more efficient operation is possible compared to conventional systems in which a generator is connected to the prime mover. Furthermore, since a generator is not used, there are no restrictions on handling.

Example FIG. 1 shows a first embodiment of the invention.

An electric motor (3) is connected to a load (1), for example a pump or a compressor, via a suitable coupling (2). The electric motor (3) is further connected to a prime mover (5) such as a diesel engine via a clutch (4), and an exhaust heat recovery boiler (8) is connected to the prime mover (5).

This power unit includes a selective control system that selectively supplies power from the electric motor (3) and the prime mover (5) to the load (1) by controlling the electric motor (3), the clutch (4), and the prime mover (5). A device (7) is provided, and the electric motor (8) is connected to the electric motor (8) through the contacts (8) of the electromagnetic switch (MS contacts) and the contacts (9) (MC contacts) of the electromagnetic contactor provided thereon.
and the clutch (4) is connected to the power source (lG). Then, the electric motor (3) is driven by turning on (closed) the MS contact (8), and stopped by turning off (opened) the MS contact (8). Also, M
By turning on (closed) the C contact (9), the clutch (4) is turned on (connected state), and the prime mover (5) is connected to the electric motor (3) and the load (1) via it. ,
By turning off (opening) the MC contact (9), the clutch (4) is turned off (disconnected) and the prime mover (5) is disconnected from the electric motor (3) and load (1).

A power usage detection device (IB) that detects the power usage of the power system is connected to the control device (7).

Then, the selection control device (7) controls the MS contact (8), the MC contact (9), and the prime mover (5) based on the power used in the power system, thereby transferring the power from the electric motor (i) to the load. (1) and motor operation that supplies power from the prime mover (5) to the load. That is, the electric motor is operated while the power consumption is below the set value, and the prime mover is operated when the power consumption exceeds the set value. Note that the set value for this switching is set in advance in the control device (7).

Next, the operation of the above-mentioned power plant will be explained in detail with reference to the flowcharts shown in FIGS. 2 to 4.

As shown in Figure 2, when starting the operation of the power plant, first check the power consumption of the power system (Step 1), and if the power consumption is less than the set value, start the motor operation.Step 2
), if it is larger than the set value, the prime mover operation is started (step 3).

The motor should be operated with the MC contact (9) turned off.
Start by turning on the S contact (8) and driving the electric motor (3). At this time, since the MC contact (9) is off, the clutch (4) is off and the prime mover (5) is disconnected from the electric motor (3) and the load (1). ) is supplied to the load (1) only. When the motor starts operating, check the power consumption (
Step 4): The motor continues to operate as long as the power consumption is below the set value. The prime mover operation is started by starting the prime mover (5) with the MS contact (8) turned off and the MC contact (9) turned on. At this time, M
Since the C contact (9) is on, the clutch (4)
is on, the prime mover (5) is connected to the electric motor (3) and the load (1) via it, and the MS contact (8) is off, so the electric motor (3) Power is not supplied to the motor and it is in a no-load state, and the prime mover (5
) is supplied to the load (1) only.

When the prime mover starts operating, check the power consumption (step 5).
), the prime mover continues to operate as long as the power consumption is greater than the set value. Note that when the prime mover is in operation, the exhaust heat of the prime mover (5) is recovered by the exhaust heat recovery boiler (8) to effectively utilize thermal energy.

When the power consumption becomes larger than the set value in step 4 while the electric motor is operating, the motor operation is switched to the prime mover operation (step 6), and the process proceeds to step 5, where the prime mover operation continues while the electric power used is greater than the set value. Details of this switching operation are shown in FIG. That is, first,
Start the prime mover (5) Step 81), prime mover (5)
The rotational speed of the motor (3) is adjusted to synchronize it with the electric motor (3) (step 82). The rotation speed of the electric motor (5) can be set in advance by considering the slip value, but it may also be detected by attaching a tachometer such as a pulse generator. Once the prime mover (5) is synchronized with the electric motor (3), the MC
The contact (9) is turned on and the clutch (4) is turned on (step 63). Thereby, the prime mover (5) is connected to the load (1) via the electric motor (3). Next, the rotational speed of the prime mover (5) is slightly increased to transfer the load to the prime mover (5) (step B4), and the electric motor (3) is placed in a no-load state (step 65). Note that the fact that the electric motor (3) is in a no-load state can be detected from the rotational speed of the prime mover (5) or the current value of the electric motor (3). And finally, turn off the MS contact (8) (step 8B
). As a result, the electric motor (3) becomes completely unloaded, and the load (1) is driven by the power from the prime mover (5).

If the power consumption falls below the set value in step 5 while the prime mover is operating, the prime mover operation is switched to electric motor operation (
Step 7) Proceeds to step 4, where the machine continues to operate the motor while the power consumption is less than or equal to the set value. Details of this switching operation are shown in FIG. That is, first, the MS contact (8) is turned on to drive the electric motor (3) (step 71), and the starting of the electric motor (3) is completed (step 72).
). Completion of starting the electric motor (3) is detected by a timer, etc., and then the rotation speed of the prime mover (5) is adjusted to start the electric motor (3).
3) (step 73). In the case of a load that does not change much, the prime mover (
5) is detected to be synchronized with the electric motor (3). Note that the operation in step 73 is necessary when the clutch (4) is a pawl clutch, but is not necessary when the clutch (4) is a friction clutch. If the prime mover (5) is synchronized with the electric motor (3), M
The C contact (9) is turned off, the clutch (4) is turned off, and the prime mover (5) is disconnected from the electric motor (3) and the load (1) (step 74). And finally, the prime mover (5)
In step 75), the load (1) is driven by the power from the electric motor (3).

By repeating such operations, the electric motor is operated as long as the power used is below the set value, and when the power used exceeds the set value, the motor is operated.

Note that the above control can also be performed using a hardware circuit.
Further, it can also be performed by software using a micro combinator or the like.

FIG. 5 shows a ji2 embodiment.

In this case, a reducer (11) is connected to the load (1) via a coupling (2), and an electric motor (8) and a prime mover ( 5) are connected. Although not illustrated, this power unit is equipped with a selection control device similar to that of the first embodiment, and by controlling these two clutches (12) and (13), the electric motor is operated. and the prime mover operation is switched. That is, by turning on the first clutch (12) and driving the electric motor (3) while the second clutch (13) is turned off and the prime mover (5) is stopped, the electric motor (3) is turned off. Only the load (1) is connected to perform motor operation.

Conversely, with the first clutch (12) turned off and the electric motor (3) stopped, the second clutch (13) is turned off.
) is turned on to start the prime mover (5), only the prime mover (5) is connected to the load (1), and the prime mover is operated.

The rest is the same as in the first embodiment.

FIG. 6 shows a third embodiment.

In this case, the load (1) is connected to the clutch (14) (1), respectively.
An electric motor (3) and a prime mover (5) are connected via a motor (5). Although not shown, this power plant is also provided with a selection control device similar to that of the first embodiment, and by controlling these two clutches (14) and (15) with this device, the second As in the embodiment, electric motor operation and prime mover operation are switched.

The rest is the same as in the first embodiment.

Effects of the Invention According to the peak load countermeasure power device of the present invention, as described above, when the power consumption of the power system exceeds a set value, power from the prime mover is selectively supplied to the load, so that the peak load can be reduced. can be suppressed to prevent abnormally high power consumption. Since the power of the prime mover is directly supplied to the load, energy loss is reduced and more efficient operation is possible compared to conventional systems in which a generator is connected to the prime mover. Furthermore, since a generator is not used, there are no restrictions on handling.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a peak load countermeasure power plant showing a first embodiment of the present invention, FIGS. 2, 3 and 4 are flow charts showing an example of the operation of the power plant, and FIG. A drawing corresponding to FIG. 1 showing the second embodiment, and a drawing corresponding to FIG. 1 showing the third embodiment. (1) Load, (8) Motor, (4) (1
2) (13) (14) (15)...Clutch, (
5)... Prime mover, (7)... Selection control device, (8)
...MS contact, (9)...MC contact, (16)...
・Power usage detection device. that's all

Claims (1)

[Claims] It detects the power used by the electric motor and prime mover connected to the load, as well as the power system, and selectively supplies power from the motor to the load while the power used is below a set value, and when the power used exceeds the set value. A peak load countermeasure power unit equipped with a selection control means for selectively supplying power from a prime mover to a load.