JPH06225480A - Superconducting power storage apparatus - Google Patents

Abstract

PURPOSE:To provide a superconducting power storage apparatus which suppresses a load fluctuation which is applied to a power system when a stored power is regenerated with a light failure mode as low as possible and eliminates harmful influences upon other users. CONSTITUTION:A superconducting coil 1, a converter 2 which is provided between the superconducting coil 1 and a power system and converts a DC power and outputs it as an AC power and a controller 10 which controls the power regeneration time, regenerated power or variation ratio of the regenerated power of the converter in accordance with an electric energy which is stored when the stored power of the superconducting coil is regenerated to the power system are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power storage device which uses a superconducting coil and is connected to a power system.

[0002]

2. Description of the Related Art In recent years, electric power demand tends to increase year by year. Even in the daily power demand, the peak power during the daytime increases, and the demand for each hour tends to expand. As a countermeasure, various power storage devices are being developed in order to level the load. The application of this power storage device depends on the scale of the installed power system and the device itself. In addition to the load leveling described above, power fluctuation suppression, voltage fluctuation suppression, and load fluctuation compensation (frequency fluctuation) for stable power supply It is also used as a means such as suppression. As means for storing electric power, research and development such as superconducting power storage, battery storage, compressed air storage, and flywheel storage are under way.

FIG. 6 shows a structural example of a superconducting power storage device using a superconducting coil as a storage facility. In FIG. 6, the superconducting coil 1 is connected to the power system via the converter 2. On the AC side, an instrument transformer 3 and a current transformer 4 for detecting active power and reactive power output from the conversion device 2 are connected, and the output thereof is input to the control circuit 5. The control circuit 5 obtains active power and reactive power from the outputs of the instrument transformer 3 and the current transformer 4, compares these values with externally applied active power reference Pref and reactive power reference Qref, and calculates the deviation thereof. The value is output as the operation control amount of the converter 2.

[0004]

By the way, in such a superconducting power storage device, there is a problem in processing energy (stored power) stored in the superconducting coil when an abnormality occurs.

For example, in a serious failure mode when a serious abnormality such as a superconducting coil undergoes a normal conduction transition, the storage power is attenuated by a damping resistor 6 provided in parallel with the superconducting coil, and then the apparatus is stopped. . Further, in the light failure mode when a relatively light abnormality that does not require an emergency occurs, a method is considered in which the device is stopped after the stored power is regenerated to the power system. However, the regeneration of the stored power in the light failure mode causes a disturbance (load fluctuation) in the power system. Since this load fluctuation directly affects the frequency fluctuation of the power system, if the load fluctuation exceeds the allowable range of the power system, it will adversely affect other customers.

[0006] Therefore, an object of the present invention is to provide a superconducting power storage device that suppresses the load fluctuation applied to the power system when regenerating the stored power in the light failure mode and does not adversely affect other consumers. Especially.

[0007]

In order to achieve the above object, a superconducting power storage device according to the present invention is configured to have a function of controlling regenerative time, regenerative power, a rate of change of regenerative power, etc. in a light failure mode. And

[0008]

According to the present invention, by controlling the regenerative time of the stored power regenerated from the superconducting coil, the regenerative power, or the rate of change of the regenerative power, regenerative operation can be performed while minimizing load fluctuations on the power system. Therefore, it will not affect other customers.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the superconducting power storage device of the present invention will be described below with reference to FIGS. 6 in FIG.
The same parts as those in FIG.
1 is different from FIG. 6 in that the control circuit 10 receives an output from the arithmetic unit 12 and an arithmetic unit 12 that calculates the stored power based on the output from the current transformer 11 that detects a direct current. That is, the controller 13 for controlling the regenerative electric power (or the regenerative time) is provided.

FIG. 5 shows a control sharing characteristic with respect to a general load fluctuation of the power system. It is considered that some fluctuation components are superposed on the load fluctuation, and the power system side shares the load fluctuation. As can be seen from this figure, as the load fluctuation increases, the load fluctuation cannot be absorbed by the system unless the fluctuation time is long. In other words, if the relationship between the load fluctuation and the fluctuation time is suppressed so as to be below the curve shown in FIG. 5, the load fluctuation can be completely absorbed in the power system.

The controller 13 controls the regeneration time (or regenerative power) so that the stored power is regenerated within a range that the power system can absorb, in consideration of the control sharing characteristic of the power system. For example, when the stored power is regenerated in the state where it is stored, if the regenerated time becomes short (the regenerated power is large), the stored power (J) = regenerative power (W) × regeneration time (s)
Therefore, the regenerative power becomes large (regeneration time is short), the load fluctuation due to regeneration cannot be absorbed by the system, and the frequency rises as a result, which adversely affects other consumers. on the other hand,
If the regeneration time is sufficiently long (regeneration power is small), load fluctuations due to regeneration can be absorbed by the system, and no problematic frequency fluctuations will occur. Here, the correspondence between the stored power and the regenerative time (or regenerative power) is arbitrarily set in consideration of the control sharing characteristic of the upper system in which the superconducting power storage device is installed and the regenerative time that the storage device can tolerate. is there. Further, when the regenerative time that the storage device can tolerate during a minor failure differs greatly depending on the failure item, it is possible to perform finer control by providing a function of selecting the maximum regeneration time in accordance with the failure item.

In the embodiment shown in FIG. 1, the stored electric power is calculated from the direct current and used as the quantity for determining the regenerative time. However, the fluctuation of the system frequency during regeneration is detected. Almost the same effect can be expected by using that value. [Other Embodiment 1]

Another embodiment 1 of the superconducting power storage device of the present invention will be described below with reference to FIGS. 2 and 5. 2, the same parts as those in FIG. 6 are designated by the same reference numerals and the description thereof will be omitted. The difference between FIG. 2 and FIG. 6 is that the control circuit 20 is provided with a controller 21 for controlling the rate of change of regenerative power.

When the stored power is regenerated, the most severe point for the system to absorb the regenerated power (= load fluctuation) is the portion where the regenerated power changes abruptly (rise and fall portions).
Therefore, it is desirable that the rate of change in regenerative power in this portion be as gentle as possible.

It has already been described that the load fluctuation can be absorbed on the system side by controlling so that the relationship between the load fluctuation and the fluctuation time is below the curve shown in FIG. This corresponds to the relationship between the load fluctuation and the fluctuation time (curve in FIG. 3). Therefore, if the rate of change of regenerative power is controlled so that it falls within the range that can be absorbed by the system (within the allowable range) in consideration of the control sharing characteristic of the upper system where the superconducting power storage device is installed, frequency fluctuations will not occur. It will not adversely affect other customers. [Other Embodiment 2]

Another embodiment 2 of the superconducting power storage device of the present invention will be described below with reference to FIGS. 3 and 4. In FIG. 3, a switch 31 for switching a control loop and a delay element 32 are provided inside the control circuit 30 as means for controlling the rate of change of regenerative power. The switch 31 has a function of switching the control loop according to the presence or absence of a power regeneration command in the light failure mode. When there is a power regeneration command in the light failure mode, the operation control amount of the converter is determined via the control loop (2). Delay element 32 provided in the control loop (2)
Acts to gently suppress the rate of change in regenerative power (rise and fall portions). FIG. 4 shows the difference in the operation control amount with and without the delay element 32.
As can be seen from FIG. 4, the rising and falling portions of the regenerative power can be gently suppressed by interposing the delay element. Here, if the constant of the delay element is set in consideration of the control sharing characteristic of the upper system where the superconducting power storage device is installed, it should be within the range (within the allowable range) in which the system can absorb the load fluctuation due to power regeneration. This makes it possible to prevent frequency fluctuations and adversely affect other consumers.

[0017]

According to the present invention, since the regeneration time of the electric power from the superconducting coil and the rate of change of the electric power can be controlled, the load fluctuation due to the regeneration can be suppressed within the allowable range of the power system, and other demands can be satisfied. It is possible to provide a superconducting power storage device that does not adversely affect the house.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a superconducting power storage device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a superconducting power storage device of another embodiment 1 of the present invention.

FIG. 3 is a configuration diagram showing a main part of a control circuit according to a second embodiment of the present invention.

FIG. 4 is a conceptual diagram showing a function of a delay element according to another embodiment 2 of the present invention.

FIG. 5 is a diagram showing control sharing of the power system with respect to load fluctuations.

FIG. 6 is a configuration diagram showing a conventional superconducting power storage device.

[Explanation of symbols]

 1 ... Superconducting coil 2 ... Converter 3 ... Instrument transformer 4 ... Current transformer 5, 10, 20, 30 ... Control circuit 6 ... Damping resistance 11 ... Current transformer 12 ... Storage power calculation unit 13 ... Regeneration time (regeneration) Electric power) controller 21 ... Regenerative power change rate controller 31 ... Switching unit 32 ... Delay element

Claims (4)

[Claims] 1. A superconducting coil, a converter which is interposed between the superconducting coil and the power system and outputs DC power as AC power, and electric power stored when the stored power of the superconducting coil is regenerated to the system. A superconducting power storage device, comprising: a control circuit for controlling a regeneration time of electric power by the conversion device according to an amount. 2. The superconducting power storage device according to claim 1, wherein the control circuit controls the regenerative electric power according to the amount of electric power stored in the superconducting coil. 3. The superconducting power storage device according to claim 1, wherein the control circuit controls a rate of change of regenerative power from the superconducting coil. 4. The superconducting power storage device according to claim 1, wherein the control circuit is provided with a delay element for gently suppressing the rate of change of the regenerative power from the superconducting coil.