JPH0412628A - Power supply system - Google Patents

Abstract

PURPOSE:To reduce a power receiving system capacity from a commercial power system by connecting a flywheel generating system in parallel to a private power generating system and performing combined operation therewith. CONSTITUTION:In a flywheel generating system 8, a generator motor(G/M)9 is used for both a generator(at power generation time) and an electric motor(at power accumulation time). That is, input power from a power converter Pc11 is accumulated as rotational energy in a G/M rotational part and a flywheel 10, directly coupled to the G/M rotational part, by operating first the G/M9 as the electric motor at the power accumulation time. On the other hand, power is supplied by converting the rotational energy into electric energy, by functioning the G/M9 as the generator at the power generation time. In this way, peak power, received from a system bus bar 2, can be reduced.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a power supply system for a power load that is used in the steel, cement, paper manufacturing, etc. industries and consumes unsteady power.

[Conventional technology]

FIG. 5 is a basic conceptual diagram showing, for example, the power equipment of a steel plant having an in-house power generation system. In the figure, 1 is the steel plant equipment, 2 is the system bus, and 3 is the steel plant equipment.
is a breaker that separates steel plant equipment 1 from system bus 2,
4 is a power receiving transformer, 5 is a private power generation system, and particularly a turbine 6 and a generator 7 are illustrated with emphasis. Note that the private power generation system 5 may not exist depending on the plant. Next, the relationship between the power load required by a steel plant and the operation of power equipment will be explained. First, FIG. 6 shows, as an example, a specific pattern of electric power load required by a steel plant. Generally, in power load equipment such as a steel plant, unsteady power in the form of a rectangular wave is consumed over time as shown in FIG. This power change is required, for example, as driving power for a mill motor when a steel plate is fed to a roller portion in a rolling plant, or for an electric furnace. FIG. 6 is an example of an electric furnace. As shown in the figure, this power change is extremely steep, and may sometimes have an adverse effect on the power system, such as frequency fluctuations. Furthermore, if there is no private power generation system, the power receiving equipment for this load power needs to have a capacity (22 MW in this case) for the peak load, and the power receiving equipment itself becomes excessive. Next, consider a case where a private power generation system 5 is installed in such a plant. FIG. 7 shows the relationship between the operating pattern of the private power generation equipment and the required power load when the private power generation system 5 is added. As the private power generation system 5, a turbine generator or the like driven by coal-fired power is usually used, but with conventional power generation equipment such as a turbine generator, power cannot be suddenly started up and stopped due to system operation. For example, the load followability as shown in the broken line pattern shown in FIG. 7 can be expected. Therefore, in this case, power is requested from the grid in a fluctuating pattern as shown in the hunting part of FIG.

[Problem to be solved by the invention]

As mentioned above, even when the conventional power supply system has a component power generation system, it is dependent on the commercial power grid for a considerable amount of load power fluctuation, which has negative effects such as frequency fluctuations on the commercial power grid. There were some issues, such as: Furthermore, since it is necessary to install power receiving equipment from the commercial power system with a capacity determined by the peak load, the power receiving equipment itself needs to be large, resulting in problems such as increased power receiving costs. Furthermore, in the operation of private power generation equipment, the operating range of the private power generation system is sometimes limited in order to prevent power leakage to the grid bus, or the so-called backfeed problem, due to poor load followability. This invention was made to solve the above-mentioned problems, and aims to provide a power receiving equipment for a commercial power system and a power supply system that can reduce or eliminate power load fluctuations.

[Means to solve the problem]

The power supply system according to the present invention includes a flywheel power generation system connected in parallel to a private power generation system, and the flywheel power generation system is operated as a generator when generating electric power and as an electric motor when storing electric power. Departure i! A motor consisting of an electric motor, a flywheel that is directly connected to the rotating part of the generator motor and stores rotational energy, and a power converter that is installed between the generator motor and the system bus and inputs and outputs electric power to the generator motor. It is.

[Effect]

The flywheel power generation system in this invention is connected in parallel with a private power generation system, and by operating in combination with the private power generation system, the capacity of the power receiving system from the commercial power system is reduced, and the power generation system of the private power generation system with poor load following ability is reduced. The power load pattern required by the power load is formed into an arbitrary shape while the operation is performed within the permissible operating range.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the same parts as in FIG. 5 are designated by the same reference numerals. In FIG. 1, reference numeral 8 indicates a flywheel power generation facility, and the basic configuration of the flywheel power generation system is shown in FIG. In FIG. 2, 9 is a generator motor, 10 is a flywheel mechanically directly connected to the generator motor 9 (however, there may be no flywheel), 11 is a power converter made of power electronics, and 12 is an excitation motor. Show the device. In addition, the flywheel power generation system 8 includes a power converter 11 connected to a generator motor 9 as shown in FIG.
There are two system configurations: one is placed on the primary side of the t! Motive (G/M) 9, (a) Flywheel (F/M) directly connected to the G/M rotating part
W) 10, (There may be cases where there is no F/W.) n) Installed between 07M9 and system bus 2 and transmitting power to 07
It consists of a power converter (Pc) 11 that inputs and outputs to M. First, the operating principle of the flywheel power generation system 8 itself will be explained. In this flywheel power generation system 8, 07M9 is used both as a generator (when generating electric power) and an electric motor (when storing electric power). That is, when storing power, C/M9 is first operated as an electric motor, and converts the power input from power converter Pc1l into G
F/WIO directly connected to /M rotating part and G/M rotating part
It stores energy as rotational energy. On the other hand, when generating electricity, 07M9 functions as a generator to convert rotational energy into electrical energy and supply electricity. An example of the pattern of generating and storing power is shown in FIG. As shown in the figure, the G/M90 rotational speed changes repeatedly in a series of operations, and the frequency of 07M9 also changes corresponding to the rotational speed. Furthermore, even when the frequency of 07M9 changes, power converter Pc1l matches the frequency of the output of power converter Pc1l in FIG. 2, or the output of 07M9 itself, to the frequency of the grid or the plant that requires variable power. Installed to convert electricity. This flywheel power generation system is a system that combines a flywheel with extremely high energy storage density and power electronics that boasts high-speed response, and the output response of the entire device is capable of responding to input/output changes exceeding IOMW/S. Become. Next, a case will be described in which a steel plant flywheel power generation system 8 having an in-house power generation system is applied. Steel plants require a rectangular wave power load pattern as shown by the solid lines in Figures 4, 6, and 7, but when this power generation equipment is applied, energy is stored during periods of low load, and That energy can be supplied during periods when large loads are required. Figure 4 shows a specific example of energy storage when the flywheel power generation system 8 is applied to an electric furnace. This shows the relationship between emissions. In the figure, private power generation equipment is operated according to the pattern shown by the broken line. In the figure, El represents the energy stored in the flywheel power generation equipment from the private power generation equipment, and E2 represents the energy released from the flywheel power generation system 8 to the load. (If the loss in the flywheel power generation system 8 is ignored, 2xEz=E+ in FIG. 4.) In the above embodiment, one steel plant is used as a load requiring variable power as a private power generation system and a flywheel power generation system. Although examples of one system for each are shown, it is not necessary that each of these systems has a single configuration, and an arbitrary number of systems may be combined. In this case, if the flywheel power generation system is composed of a plurality of systems, an arbitrary number of flywheel power generation systems will be operated corresponding to the load power determined by the operating level of the plant.

【Effect of the invention】

As described above, according to the present invention, a private power generation system and a flywheel power generation system are connected in parallel to a plant that requires variable power, and the private power generation system with poor load followability can be operated within an allowable operating range. As the power load pattern required by the plant is formed into an arbitrary shape, the peak power received from the grid bus can be reduced, equipment capacity and operating costs can be kept low, and the power received can be completely eliminated. There is an effect that can be achieved. Furthermore, since the private power generation system can be operated without worrying about load followability, there is an effect that the private power generation system can be operated without restrictions in an expanded operating range.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram of a combination of a flywheel power generation system and a private power generation system according to an embodiment of the present invention, FIG. 2 is a basic configuration diagram of the flywheel power generation system in FIG. 1, and FIG. Fig. 4 is an explanatory diagram showing the energy storage and release pattern to which this invention is applied, Fig. 5 is a configuration diagram of a conventional private power generation system, and Fig. 6 is a diagram of the basic operation pattern of the flywheel power generation system shown in Fig. 6. FIG. 7 is an explanatory diagram of a power load pattern of a plant (electric furnace), and is an explanatory diagram showing an operation pattern when a private power generation system is applied to the power load pattern of FIG. 6. In the figure, 2 is the grid bus, 5 is the private power generation system, and 8
is a flywheel power generation system, 9 is a generator motor, 10 is
is a flywheel, and 11 is a power converter. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] In a power supply system that supplies power from a grid bus or private power generation system to power load equipment that consumes unsteady power in a rectangular wave shape over time, the power generator is operated in parallel with the private power generation system, and when power is generated, a generator-motor that is operated as a generator-motor and is operated as an electric motor when storing power; a flywheel that is directly connected to the rotating part of the generator-motor and stores rotational energy; and a flywheel that is installed between the generator-motor and the system bus and that stores electric power. A power supply system comprising a flywheel power generation system having a power converter that inputs and outputs to a generator motor.