JPS6353771B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a protection device for a regenerative substation for electric railways,
In particular, the present invention relates to a protection device that prevents device failure due to commutation failure in a thyristor converter.

Figure 1 shows the main circuit configuration of a regenerative substation for electric railways. The thyristor converter 1 functions as a forward converter during the power running operation of the electric train 2, and converts AC power into DC power at the rated voltage by controlling the phase of the thyristor. The DC output of the thyristor converter 1 is supplied and regenerated to the train 2 through the commutation reactor 3 and the regenerative power running switching device 4. The regenerative power running switching device 4 turns off the thyristor switches 4 ₁ and 4 ₂ during power running of the train 2, and switches the cut-off diode 4 from the converter 1 to the off state.
₃ - Train 2 - Cut-off diode 4 ₄ - Configures a power running circuit through commutation reactor 3, turns on thyristor switches 4 ₁ and 4 ₂ during regeneration of train 2, and disconnects thyristor switch 4 ₁ from train 2.
- Commutation reactor 3 - Converter 1 - Thyristor switch 4 Constructs a regenerative operation circuit using the illustrated current I through ₂ . During this regeneration, the thyristor converter 1 functions as an inverse converter.

In such a regenerative substation for electric railways, when a thyristor commutation failure occurs in the thyristor converter 1 during regenerative operation, the current path of the commutation reactor 3 is immediately cut off, and a high voltage is generated in the reactor 3. Due to the voltage, there was a risk that peripheral equipment would be damaged, such as dielectric breakdown of the converter 1, and that the substation would stop functioning.

SUMMARY OF THE INVENTION An object of the present invention is to provide a protection device that promptly dissipates the energy of a commutation reactor when commutation of a thyristor converter fails, thereby preventing device failure.

According to the present invention, when a commutation failure of a thyristor converter is detected, the upper and lower arms of the thyristor converter are forcibly fired, and one thyristor switch of the regenerative power running switching device is fired, so that the current in the commutation reactor is It forms a circulation path and dissipates its energy, and the remaining one of the thyristor switches.
The feature is that the regenerative current path is cut off by extinguishing one arc.

Hereinafter, one embodiment of the present invention will be described in detail.

FIG. 2 shows a schematic configuration of a protection device according to the present invention. The protection device 5 starts a protection operation by detecting commutation failure of the converter 1 from the detected voltage of the output voltage detector 6 of the thyristor converter 1. The protection mode is such that the energy of the commutation reactor 3 is transferred to the converter 1, the thyristor switch _{4 2 ,} and the diode. ₄ is consumed in a circulation path that passes through three commutation reactors. At the same time, the thyristor switch ₄₁ is controlled to extinguish the arc, and the regenerative current from the train 2 is cut off, preventing the regenerative current from flowing into the current path of the commutation reactor, thereby reducing the energy consumption of the commutation reactor. Hurry up. Further, the remaining thyristors of the converter 1 are extinguished to disconnect from the alternating current side.

When the energy dissipation of the commutation reactor 3 is completed, the protection device 5 stops the protection control in response to the zero current detection signal from the output current detector 7 of the thyristor converter 1, and returns to the normal substation function.

FIG. 3 shows a specific configuration of the protection device 5. A protection device 5 indicated by a broken line block takes in the detected voltage of the voltage detector 6 as a detection input of a commutation failure detection circuit ₅₁ , and determines that commutation has failed when the detected voltage falls below a certain value. A logic "1" signal is obtained at the judgment output. This commutation failure detection circuit is realized, for example, by the configuration shown in FIG. In Fig. 4, the DC output of the voltage detector 6 is applied to a series circuit of a resistor R ₁ and a photocoupler input diode D ₁ , and when the level of the detected voltage falls below a certain value, the input diode D ₁ switches on the previous light. The light changes from the state to the light-off state. This change causes the output transistor T _r1 of the photocoupler to change from an on state to an off state, thereby obtaining a logic high level state at its output.

The protection device 5 inputs the detection signal of the commutation failure detection circuit ₅₁ to one input of the AND circuit ₅₂ , and inputs the start signal corresponding to the operation and stop state of the converter 1 to the other input (starting during operation). When both conditions are satisfied simultaneously, a logical "1" output is obtained from the AND circuit ₅₂ , and the memory circuit (flip-flop) ₅₃ is changed from the reset state to the set state. The set output of the memory circuit ₅₃ is used as a start command for the gate cutoff signal generation circuit ₅₄ and the gate on signal generation circuit ₅₅ .
The gate shear failure signal generation circuit 5 ₄ is configured to detect the upper and lower two phases of U, V, X, and Y of each phase gate circuit X, Y, Z, U, V, and W provided in the gate circuit 8 of the thyristor converter 1. ignition gate signals of the thyristors T _hU , T _Tv , T _hx , and T _hY of the converter 1 are generated to extinguish the respective thyristors. The gate-on signal generating circuit ₅₅ generates gate-on signals for the upper and lower phases of W and Z of each phase gate circuit, and fires the thyristors T _hw and T _hz of the converter 1.

Further, the gate shear breakage signal generation circuit 5 ₄ is connected to a thyristor switch 4 ₁ provided in the regenerative power running switching device 4 .
Of the gate circuits 9 of 4 ₂ , the thyristor switch 4 ₁
A gate cut-off signal is applied to the gate circuit 9 ₁ , and the thyristor switch 4 ₁ is forcibly turned off by the gate circuit 9 ₁ . The gate-on signal generating circuit ₅₅ gives a gate-on signal to the gate circuit ₉₂ of the gate circuits 9, and the gate circuit ₉₂ forcibly fires the thyristor switch ₄₂ .

The zero current detection circuit ₅₆ of the protection device 5 inputs the detection signal of the current detector 7, and obtains a logic "1" output when the detection signal becomes zero, and this output is used as a reset signal for the memory circuit ₅₃ . used.

Such a protection device 5 is integrated with the control device of the regenerative substation. The control device of the regenerative substation uses the detection signal V _T of the overhead line voltage that supplies power to train 2 and the set voltage.
The comparator 10 detects the magnitude of V _s , and the comparator 1
0 serves as a determination unit for regeneration and power running, giving on/off commands to the gate circuits 9 of the thyristor switches 4 ₁ and 4 ₂ and determining whether the thyristor converter 1 is operated as a sequential converter or an inverse converter. A switching signal is given to analog switches 11A and 11B. The analog switch 11A switches and takes out the respective outputs of the converter 12 1 which obtains the detection voltage of the DC side voltage detector 6 of the thyristor converter ₁ with the same polarity and the converter 12 ₂ which obtains the detection voltage with the opposite polarity.
B is each DC voltage setting device 1 for regeneration and power running
Switch the set voltage of 3 ₁ and 13 ₂ and take out. The outputs of both analog switches 11A and 11B are matched and amplified by a voltage control amplifier 14, and the amplified output is used as a phase control command to give a gate signal to the gate circuit 8 of each phase from a phase control circuit 15.

During regenerative operation by this control device, when a commutation failure occurs in the thyristor converter 1, the protection device 5 sets the memory circuit ₅₃ upon detection of the commutation failure, and uses this set output to set the W, W of the thyristor converter 1,
The Z-phase thyristor is forcibly turned on, the X, Y, U, and V-phase thyristors are turned off, and the thyristor switch 4 ₁ of the regenerative power running switching device 4 is turned off, and the thyristor switch 4 ₂ is turned on to circulate the current in the commutation reactor 3. It forms channels and dissipates its energy. At this time, the AC input side and the DC side are separated by the thyristor converter 1, and the train 2 side is separated from the circulating current path, and only the energy of the commutation reactor 3 is quickly dissipated in the current circulating path. To prevent abnormal heat generation caused by excessive current flowing through thyristors and diodes entering a circulation path.

After the current in the commutation reactor 3 is sufficiently dissipated, the memory circuit 5 ₃ is detected by the zero current detection circuit 5 ₆ .
and return to normal substation operation.

As described above, according to the present invention, by firing the upper and lower phases of the thyristor converter and firing one thyristor of the thyristor switch, a current circulation path of the reactor is formed, and the remaining part of the thyristor converter is turned on. In order to extinguish the phase of the thyristor switch and disconnect the current path from the AC power supply side, and extinguish the other thyristor of the thyristor switch to disconnect the regenerative current path from the load side, commutation is performed in the thyristor converter. This has the effect of quickly dissipating the energy of the commutation reactor in the event of a failure, thereby reliably preventing damage to other circuit equipment. Further, the protection device of the present invention can be simplified in that it only needs to generate a control signal using a control device of a substation.

[Brief explanation of the drawing]

Figure 1 is a main circuit configuration diagram of a regenerative substation for electric railways, Figure 2 is a schematic configuration diagram of a protection device according to the present invention, and Figure 3 is a schematic configuration diagram of a protection device according to the present invention.
The figure shows the specific configuration diagram in Figure 2, and Figure 4 shows the 3rd diagram.
It is a commutation failure detection circuit diagram in the figure. DESCRIPTION OF SYMBOLS 1... Thyristor converter, 2... Electric train, 3... Commutation reactor, 4... Regenerative power running switching device, 5... Protective device, 5 ₁ ... Commutation failure detection circuit, 5 ₂ ... AND circuit,
5 ₃ ...memory circuit, 5 ₄ ...gate cutoff signal generation circuit, 5 ₅ ...gate on signal generation circuit, 5 ₆ ...zero current detection circuit, 6...voltage detector, 7...current detector,
8...Gate circuit of thyristor converter, 9...Gate circuit of regenerative power running switching device.

Claims (1)

[Claims] 1. A thyristor converter that is controlled to have both the functions of a forward converter and an inverse converter, a commutation reactor inserted on the DC side of this thyristor converter, and a connection between the DC side of the thyristor converter and the train overhead wire. A cut-off diode is provided in the current path that supplies DC power from the thyristor converter side to the train side, and a regeneration thyristor switch that switches the current path that regenerates DC power from the train side to the thyristor converter side. In a regenerative substation for electric railways equipped with a power running switching device, when a commutation failure of the thyristor converter is detected, the thyristors for one phase of the upper and lower phases of the thyristor converter are forcibly ignited, and the remaining thyristors are forcibly extinguished. A protection device for a regenerative substation for electric railways, comprising a control circuit for forcibly igniting one of the thyristor switches of the regenerative power running switching device and forcibly extinguishing the other thyristor switch.