JPH0780429B2 - DC electric railway substation equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conversion facility for a DC electric railway equipped with a power regeneration function by reverse power conversion, and in particular to a high power substation requiring high efficiency operation. Substation equipment suitable for

[Background of the Invention]

As a substation for a DC electric railway, a self-exciting converter (a converter for both forward and reverse operations that can convert AC to DC and DC to AC) is used to enable power regeneration control. Equipment has come to be used, but in such a conventional substation equipment, as shown in FIG. 4, a self-exciting converter 5 is used alone to supply DC power to a load 6. It was becoming. In addition, this 4th
In the figure, 1 is an AC power supply system, and 4 is a transformer for a converter. Then, at the time of power regeneration, the DC power from the load 6 is inversely converted by the excitation-type converter 5 and absorbed by the power supply system 1 via the transformer 4.

However, since the self-excited converter has commutation loss,
The snubber loss, which has a relatively low efficiency and shows a large percentage during commutation loss, is related to the installed capacity of the load, almost independently of the load. This characteristic becomes a net, and despite the advantages of low harmonics and power factor control,
Conventionally, it was difficult to apply it as a large-capacity substation facility.

Therefore, in order to make up for such a point, if it is encouraged, it is disclosed in Japanese Patent Laid-Open No.
As disclosed in Japanese Patent No. 185, there is proposed a system in which a diode rectifying device is provided in parallel with a self-exciting converter, and the self-exciting converter handles only regenerative electric power.

However, this method has a drawback in that the power conversion capability of the self-exciting converter can be utilized only during power regeneration control, and the equipment capacity is increased more than necessary, resulting in significant cost up.

[Object of the Invention]

The object of the present invention is, except for the drawbacks of the prior art described above, that the utilization factor of the installed capacity is sufficiently high, and that it is applied to a large-capacity substation so that high efficiency can be obtained. To provide railway substation equipment.

[Outline of Invention]

In order to achieve this object, the present invention provides a rectifier for forward conversion, which is provided with a converter for both forward and reverse, and which has a power regeneration control function. While using the device, a control device for controlling the ratio of the conversion power of the self-excited voltage converter to the output power of the rectification device is provided, and by this control device, the ratio of the output power of the rectification device in the load power, It is characterized in that it is controlled so that it is always higher than the conversion power of the self-excited voltage type converter.

Example of Invention

Hereinafter, for the DC electric railway substation equipment according to the present invention,
This will be described in detail with reference to the illustrated embodiment.

FIG. 1 is an embodiment of the present invention. In the figure, 2 is a transformer for a rectifier, 3 is a rectifier consisting of bridge-connected diodes, 7 is a vacuum circuit breaker, 8 is a high speed circuit breaker, 9
Is a disconnector, 10 is a DC reactor, 11 is a controller,
The AC power supply system 1, the transformer 4 for the converter, the self-excited converter 5, the load 6 and the like are the same as in the conventional example of FIG. 4, but in this embodiment, the self-excited converter 5 is shown in FIG. As shown in the figure, a flywheel diode is connected in parallel with a switching element such as a CTO (gate turn-off thyristor). PWM
(Pulse width modulation) control is performed to obtain both forward and reverse conversion operations.

The rectifier 3 converts (rectifies) the AC power supplied from the AC power supply system 1 via the vacuum circuit breaker 7 and the transformer 2 into a DC power, and loads it via the high speed circuit breaker 8 and the disconnector 9 ( It works to supply DC current I _SR to electric car 6.

The converter 5 converts the AC power supplied from the power supply system 1 via the vacuum circuit breaker 7 and the transformer 4 into DC power, and loads it via the high speed circuit breaker 8, the disconnector 9 and the DC reactor 10. 6 is supplied with a DC current I _CON, and when the terminal voltage of the load 6 rises above a predetermined value, the DC power sent from this load is converted into AC power and the AC power supply system 1 absorbs it. Function to perform power regeneration control.

At this time, since the conversion device 5 is a self-exciting voltage type forward / reverse conversion device, when the power conversion operation changes from forward conversion to reverse conversion, on the contrary, when the reverse conversion operation changes to forward conversion operation. In either case, the polarity of the DC side voltage does not change, so no switching operation is required.Therefore, there is no risk of a no-voltage period appearing, and as a result, the power regeneration operation is invalidated. Since there is no fear of causing a shock to the running of the train, and there is no fear of a circulating current due to the switching operation, it is possible to eliminate the risk of a power supply power factor reduction due to an unnecessary current.

The control device 11 detects the output side voltage and the current I _SR of the rectifying device 3 and supplies a control signal (PWM control signal) to the conversion device 5 in accordance with the detected voltage or current I _SR , so that the load current I _l flowing to the load 6 is Current I _SR from rectifier 3 and current I from converter 5
Control so that the ratio of _CON is in a predetermined state,
The control necessary for the power regeneration control described above is performed.

Next, the operation of this embodiment will be described with reference to FIGS.

These figures show the rectifying device 3 and the converting device 5 by the control device 11.
Shows the contents of the current sharing control of the
I _l , and the vertical axes represent currents I _SR and I _CON , respectively.
Therefore, the current (I _SR + I _CON ) shown by the solid line becomes the current I _l . Also, in the figure, the right side of the vertical axis shows a state where the current I _l is supplied to the load 6, and the left side shows the current I _l from the load 6.
Represents the state of electric power regeneration control in which the current flows in the opposite direction. Furthermore, the alternate long and short dash line indicates the current I _CON shared by the converter 5.
, And the chain double-dashed line represents the current I _SR shared by the rectifier 3.

In these figures, first, FIG. 2 shows the case where the current sharing ratio of the rectifying device 3 and the converting device 4 is kept constant, and FIG. 3 shows when the load power exceeds the rated capacity of the rectifying device 3. This is a case where the power is supplied from the converter 5 only, and when the load power does not reach the rated capacity of the rectifier 3, the power supply from the converter 5 is stopped.

Therefore, in any of these embodiments, the control device is configured so that the ratio of the output power of the rectifying device 3 in the load power is always larger than the converted power of the self-excited voltage type conversion device 5.
It will be controlled by 11. However, in any of these cases, since the rectifying device 3 does not have the power regeneration capability, as shown on the left side of these figures, the self-exciting converter 5 shares all the current during power regeneration.

Next, the result of the control for such an embodiment of the present invention will be described.

In recent substations equipped with a standard power regeneration function for electric railways, the forward conversion capacity is 2000-6000KW, and the reverse conversion capacity is 500-
It is 1000KW.

Therefore, consider a case where the present invention is applied to a substation with a forward conversion capacity of 4000 KW and an inverse conversion capacity of 1000 KW. That is, the first
In the illustrated embodiment, it is assumed that the rectifier 3 has a capacity of 3000 KW and the converter 5 has a capacity of 1000 KW.

In addition, the efficiency of the rectifier 3 is 98.5% and the efficiency of the converter 5 is
95%

Then, in this embodiment, the total efficiency at the maximum output of 4000 KW is 97.6% and the loss is 95 KW.

On the other hand, if this is assumed by the system using only the converter shown in FIG. 4, the efficiency is 95% and the loss is 200 KW.

Therefore, according to this embodiment, high-efficiency operation can be performed, operation can be performed with the output of the full equipment capacity, and effective use of the equipment can be obtained.

In particular, according to the control system of FIG. 3, since the converter 5 does not operate in the low load region, it is possible to operate with the same efficiency as in the case of only the rectifier 3, and it is possible to greatly improve the efficiency at light load. become.

〔The invention's effect〕

As described above, according to the present invention, a substation facility provided with a self-excited converter for the power regeneration function can be operated with high efficiency. It is possible to easily provide a substation facility for a DC-electric railway that can be operated with high efficiency at all times and that can effectively utilize the installed capacity.

Further, in the present invention, since the voltage type forward / reverse conversion device is used as the forward / reverse conversion device, when the power conversion operation changes from the forward conversion to the reverse conversion, the reverse conversion operation changes to the forward conversion operation. In either case, the polarity of the DC side voltage does not change, so no switching operation is required.Therefore, there is no possibility that a no-voltage period will appear, and as a result, power regeneration operation will not occur. There is no fear that the train will run out of time, which will cause a shock to the running of the train, and there will be no fear of a circulating current associated with the switching operation.

[Brief description of drawings]

FIG. 1 is a system configuration diagram showing an embodiment of the present invention, and FIG.
FIG. 3 and FIG. 3 are explanatory diagrams each showing an example of a control mode in one embodiment of the present invention, and FIG. 4 is a block diagram showing a conventional example of substation equipment. 1 ... AC power supply system, 2 ... Rectifier transformer, 3 ...
Rectifier, 4 ... Transformer for converter, 5 ... Self-exciting converter, 6 ... Load, 7 ... Vacuum circuit breaker, 8 ... High speed circuit breaker, 9 ... Disconnector, 10 ... DC Reactor, 11 ... Control device.

Claims (3)

[Claims] 1. A DC electric railway substation facility having a power regeneration function, a rectifier for forward conversion, a self-excited voltage type converter for both forward and reverse conversion, and the self-excited type for output power of the rectifier. A control device for controlling the ratio of the converted power of the voltage type converter is provided, and the ratio of the output power of the rectifier in the load power is
A substation facility for a DC electric railway, characterized in that the control device is configured so that a control that is always large according to the converted power of the self-excited voltage type conversion device is given. 2. The substation equipment for a DC electric railway according to claim 1, wherein the control of the ratio by the control device is configured to be a constant ratio with respect to the load power. . 3. The control of the ratio by the control device according to claim 1, wherein the conversion power of the self-exciting voltage type conversion device is made zero until the load power reaches a predetermined value. A substation facility for a DC electric railway, wherein the output power of the rectifying device is controlled to be kept at a predetermined value when the value is equal to or higher than a value.