JP2009273218A - Power accumulation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of charging/discharging operation which exceeds a design specification in a power accumulation system. <P>SOLUTION: In the power accumulation system, when an overhead wire voltage continues to be lowered for a long time due to the setting of a voltage (discharging start voltage V<SB>d0</SB>) for starting discharging accompanied by the lowering of the overhead wire voltage to a value obtained by subtracting a lowering-allowable voltage V<SB>pms</SB>from a time-average voltage V<SB>ave</SB>of the overhead wire voltage, the discharging start voltage V<SB>d0</SB>is simultaneously lowered as the voltage V<SB>ave</SB>is gradually lowered. Since the discharging is automatically stopped when the voltage V<SB>d0</SB>is lowered to the voltage V<SB>ave</SB>or below, the long-time discharging out of the specification can be prevented. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a power storage system that prevents overheating of a device due to charge / discharge operations exceeding design specifications.

  The power storage system is installed as a ground facility for power supply in electric railways at places where the train operation is hindered by voltage drops, such as far away from the substation. Power is stored, and the overhead line voltage is compensated by discharging when a voltage drop occurs when the train passes.

  Also, in the dense train section, the electric power is stored when the train passes while it is regenerating to suppress the jumping of the overhead voltage, and the electric power can be effectively used by discharging little by little during steady state. It is used practically in sections where the interval is long and the voltage drop is remarkable, or where the train operation density is high and the overhead line voltage fluctuation is large.

Usually, the power storage system performs charging / discharging operation to prevent the overhead line voltage from deviating from the normal voltage range, so the train schedule is greatly disturbed and the number of trains running at one time exceeds the design specification. There is a possibility that power is charged and discharged, the system is overheated, and stops due to the protection operation.
Even when the diagram is normal, the optimal charge / discharge start voltage does not always match in the midnight / early morning and rush hours. In the band, the discharge amount tends to be excessively large. In order to cope with both, there is a problem that when the range of the allowable overhead wire voltage is expanded, the amount of fluctuation of the overhead wire voltage becomes large.
Publication 2005-278366

  The problem to be solved is that, if the average voltage of the overhead wire fluctuates greatly due to disturbance of the train schedule, etc., the power storage system may overheat and the system may stop.

  According to the first aspect of the present invention, there is provided a railway feeder installed between substations that compensates power from the power storage device when the overhead line voltage decreases and absorbs power to the power storage device when the overhead line voltage increases. The discharge start voltage fluctuates with a change in the average voltage, and an unexpected continuous discharge operation can be prevented.

  That is, the most important feature is to prevent continuous charge / discharge out of specification by automatically varying the optimum charge / discharge start voltage according to the average voltage of the overhead wire.

  Since the power storage system of the present invention varies the charge / discharge start voltage in response to fluctuations in the overhead line average voltage, the optimum charge / discharge start voltage can be automatically set according to the load fluctuation, and charge / discharge starts at each installation location. There is no need to fine-tune the voltage. Therefore, there is an advantage that the effect of stabilizing the overhead line voltage can be maximized while suppressing excessive charge / discharge outside the specification.

  The purpose of the storage system is to be used safely under conditions where the daily load fluctuation is large and it is difficult to set the discharge start voltage, or when the diagram is disturbed and the overhead line voltage is significantly lower than normal. Realized without any fine adjustment.

  FIG. 1 is a diagram showing a storage system charging / discharging current with respect to an overhead line voltage in an embodiment of the device of the present invention.

  A value that follows the overhead wire voltage VL with a certain time constant τ is an overhead wire average voltage Vave, and a discharge start voltage is VL−Vave = 200V.

  When the overhead wire average voltage Vave is 1500 V at normal times, when the overhead wire voltage VL decreases to 1300 V or less, the power storage device starts discharging to the overhead wire, and when the overhead wire voltage exceeds 1300 V, the discharge is stopped.

  If the load is heavy during the rush hours and the overhead line average voltage Vave is 1400V, discharge does not start even if the overhead line voltage VL becomes 1300V. Start and stop discharging when the overhead wire voltage exceeds 1300V. With this operation, it is possible to suppress the operation frequency of the power storage system to the same level as compared with the normal time and to suppress unnecessary discharge operation.

In addition, when the state of the normal overhead wire average voltage 1500 V suddenly changes due to diamond disturbance, etc., and continuously drops below the discharge start voltage, the discharge operation continues at the beginning of the discharge, but only the time constant τ When time elapses, the overhead wire voltage VL becomes equal to or lower than the discharge start voltage, and the discharge operation stops.
Therefore, unexpected continuous discharge can be prevented by setting allowable maximum continuous discharge time ≦ time constant τ.

  By automatically changing the discharge start voltage in accordance with the change in the overhead line average voltage, it is possible to safely install the power storage system at any place on the route without fine adjustment on site.

It is explanatory drawing which showed the implementation method of an electrical storage system. Example 1

Claims (1)

Installed between substations to compensate for the electric power from the power storage device when the overhead line voltage decreases, and to change the average voltage of the overhead line voltage in a railway power supply facility that absorbs power to the power storage device when the overhead line voltage increases. A power storage system characterized in that the discharge start voltage fluctuates and the continuous discharge operation outside the specification is prevented.

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