JPH0522615B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a power supply switching method for an AC electric railway.

(Prior art and problems) Conventionally, power supply devices for AC electric railways, for example,
It consisted of a feeding circuit as shown in the figure. 1st
In the figure, 1a is a first overhead contact line connected to the first AC substation 2a, and 1b is a second overhead contact line connected to the second AC substation 2b. A third overhead contact line 1c is provided between the first overhead contact line 1a and the second overhead contact line 1b via sections 3a and 3b. An AC circuit breaker 4a is connected between the overhead contact lines 1a and 1c that sandwich the section 3a. An AC circuit breaker 4b is connected between the overhead contact lines 1c and 1b that sandwich the section 3b. Ground steppers 7a, 7b, and 7c are provided at predetermined locations on the rail 5 connecting the substations 2a and 2b to detect the presence of the electric vehicle 6 and supply opening/closing control signals to the circuit breakers 4a and 4b. There is. It is assumed that the electric car 6 is now traveling from the first substation 2a toward the second substation 2b, and the AC circuit breaker 4a is in a closed state and the AC circuit breaker 4b is in an open state. Next electric car 6
When the ground stepper 7c is advanced, a control signal for opening the AC circuit breaker 4a and a control signal for closing the AC circuit breaker 4b are emitted from the footstep 7c. As a result, the circuit breaker 4a is switched to the open state and the circuit breaker 4b is switched to the closed state during the period when the electric car 6 exists under the third overhead contact line 1c. Then, since the AC voltage from the second AC substation 2b is applied to the third contact line 1c and the second contact line 1b, the potential difference between the contact lines 1c and 1b becomes zero. Therefore, when the electric car 6 crosses the section 3b, no arc is generated in the section 3b. Next, when the electric car 6 advances toward the second AC substation 2b side and steps on the ground step 7b, the step 7b moves to the AC breaker 4a.
A control signal for closing the AC circuit breaker 4b and a control signal for opening the AC circuit breaker 4b are issued. As a result, the circuit breaker 4a is switched to the closed state, and the circuit breaker 4b is switched to the open state.

In the device configured as described above, when switching the power supply from the two substations by controlling the opening and closing of the AC circuit breakers 4a and 4b, due to the mechanism of the section sectional switchgear, power is inevitably supplied at the third contact line 1c. is interrupted, causing problems in driving electric cars.
In other words, if the timing of power supply switching is shifted due to a delay in the operating time of AC circuit breakers 4a and 4b,
After the AC breaker 4a is opened, the AC breaker 4b is opened.
The power supply is stopped within the time until the electric car 6 is closed, and the operation of the rotating machine (not shown) mounted on the electric car 6 is stopped. Then, until the AC circuit breaker 4b is closed and power supply is resumed, a power converter for driving and controlling the rotating machine, such as a thyristor converter, will fail in commutation and become inoperable. In other words, if the electric motor for driving the electric car 6 is a regenerative electric car that can convert the electric power generated during regenerative braking into AC using a separately excited inverter and return it to the AC system, the timing of switching the power supply is determined as described above. Misaligned train line 1
If c becomes a no-voltage state, the control elements of the separately excited inverter, such as thyristors, cannot be commutated, making regenerative operation impossible. Furthermore, even if the electric car is not equipped with a separately excited inverter, the residual voltage in the drive motor of the electric car disappears in about 1 second at most, so if the power supply voltage is absent for a long time, the electric car will completely fail. The problem is very big.

(Object of the Invention) The present invention has been made in view of the above points, and is intended to temporarily stop the operation of electric cars running under the overhead contact line that is separated by a section between the first and second AC substations. It is an object of the present invention to provide a power supply switching method for an AC electric railway that can switch the power supply from the substation at high speed without causing problems.

(Summary of the Invention) The present invention provides an electric car moving from a first AC substation to a second AC substation under a contact line that is separated by a section between the first and second AC substations. When switching between different power sources (the first AC substation and the second AC substation are shown), the voltage on the contact line caused by the residual voltage of the drive motor on the electric car side and the voltage at the second AC substation The present invention is characterized in that when the phase difference with the electric voltage falls within a predetermined range, the power supply is switched by closing the power supply path connecting the overhead contact line and the second AC substation.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. In FIG. 2, the same parts as in FIG. 1 are designated by the same reference numerals and their explanation will be omitted. 11a
is a first bridge circuit formed by bridge-connecting diodes 12a to 12d. Diode 12a
A common connection point 13a between the diode 12b and the diode 12b is connected to the first overhead contact line 1a, and a common connection point 13b between the diode 12c and the diode 12d is connected to the third overhead contact line 1c. The cathodes of the diode 12a and the diode 12c are connected to the anode of a first semiconductor circuit breaker, for example a first thyristor circuit breaker 14a, which is stationary and has a fast cut-off function. This first thyristor circuit breaker 14a
The cathode of is connected to the anodes of diode 12b and diode 12d. 11b is a second bridge circuit formed by bridge-connecting diodes 12e to 12h. A common connection point 13c between the diode 12e and the diode 12f is connected to the second overhead contact line 1b, and a common connection point 13d between the diode 12g and the diode 12h is connected to the third overhead contact line 1.
connected to c. The anodes of the diode 12e and the diode 12g are connected to the cathode of a second semiconductor circuit breaker, for example a second thyristor circuit breaker 14b, which is stationary and has a high-speed cutoff function. The anode of this second thyristor breaker 14b is connected to the diode 12f and the diode 12.
connected to the cathode of h. 15a is a fourth overhead contact line connected to the first AC substation 2a, and 15b is a fifth overhead contact line connected to the second AC substation 2b. A first autotransformer 16a is inserted between the first contact line 1a and the fourth contact line 15a, and the midpoint of the windings of this transformer 16a is connected to the rail 5. A second autotransformer 16b is inserted between the second overhead contact line 1b and the fifth overhead contact line 15b, and the midpoint of the winding of this transformer 16b is connected to the rail 5. The first and second autotransformers 16a, 16
b is a transformer for reducing communication induction disturbances caused by current flowing through the rail 5 leaking to the ground. The thyristor circuit breaker 14 detects the presence of the electric car 6 at a predetermined location on the rail 5.
Ground step 7 that supplies opening/closing control signals to a and 14b
a, 7b, and 7c are provided as shown in FIG. FIG. 3 is an equivalent circuit diagram showing the device in FIG. 3 with some parts omitted. FIG. 4 is a voltage waveform diagram of the output voltage Ea of the first AC substation 2a and the output voltage Eb of the second AC substation 2b.

Next, a method of switching power supply between different power sources in the apparatus configured as described above will be explained with reference to the switching control circuit diagram shown in FIG. Now the 1st to 3rd tram lines 1a, 1b, 1c
The overhead line voltage is detected by the first to third voltage detectors 21a, 21.
b and 21c respectively. Then, a first phase comparator 22a converts the phase of the output voltage of the first voltage detector 21a and the phase of the output voltage of the third voltage detector 21c.
Compare with. Further, a second phase comparator 22b compares the phase of the output voltage of the second voltage detector 21b and the phase of the output voltage of the third voltage detector 21c. Here, it is assumed that the electric car 6 is traveling from the first substation 2a to the second substation 2b, the first thyristor circuit breaker 14a is in the closed state, and the second thyristor circuit breaker 14b is in the open state. At this time, since the AC voltage Ea from the first AC substation 2a is applied to the third contact line 1c, the potential difference between the contact lines 1a and 1c becomes zero. Therefore, when the electric car 6 crosses the section 3a, no arc is generated in the section 3a. Next, when the electric car 6 moves forward and steps on the ground step 7c, the step 7c issues a control signal to open the first thyristor circuit breaker 14a, and at the same time, the step 7c issues the second thyristor circuit breaker 14a in FIG. Judgment circuit 23b
An ON command is issued to the first determination circuit 23a, and an OFF command is issued to the first determination circuit 23a. As a result, the first thyristor circuit breaker 14a becomes open at time _t1 shown in FIG. At this moment, the power supply to the electric car 6 is stopped, but since the electric car 6 is equipped with auxiliary equipment such as a rotating machine, the residual voltage of the auxiliary _equipment is 3 occurs on electric train line 1c. At this time, the second determination circuit 23b is connected to the second phase comparator 22b.
The voltage phase difference θ between the voltage of the second overhead contact line 1b and the voltage of the third overhead contact line 1c output from This is carried out for a predetermined time (for example, the time until two cycles have elapsed) from _t1 . Then, at time _t2 when the voltage phase difference θ is determined to be within the predetermined range, an ON command is guided from the second determination circuit 23b to the control circuit 14b' that closes the second thyristor circuit breaker 14b, and the control circuit The second thyristor circuit breaker 14b is turned on via 14b'. As a result, the electric car 6 running under the third overhead contact line 1c
Electric power is supplied from the second substation 2b via the second overhead contact line 1b, the diode 12f, the second thyristor circuit breaker 14b, the diode 12g, and the third overhead contact line 1c. In this way, the power supply to the electric car 6 running under the third overhead contact line 1c can be switched within a very short period of time, for example, within two cycles, when the residual voltage of the drive motor on the electric car side is generated. Voltage of overhead contact line 1c (residual voltage of electric car 6
Since the power supply switching is performed when the phase difference between the voltage of the second contact line 1b (feed voltage _{E b of} the second substation 2b) is within a predetermined range, Commutation failure does not occur in the converted power converter (not shown), and stable operation can be continued. When the electric car 6 travels from the second substation 2b to the first substation 2a, the same power supply switching operation as described above is performed, so a description thereof will be omitted.

Note that the range of the voltage phase difference when switching the power supply is not limited to 30° to 60°, but may be other values.
Furthermore, the power supply switching time is not limited to two cycles, but may be any other value.

(Effects of the Invention) As described above, according to the present invention, the following effects can be obtained. In other words, (1) Since the power supply from two adjacent substations is switched at high speed, for example within two cycles of the residual voltage of the drive motor on the electric car side, the electric car can continue to operate without any problems. .

(2) Since the power supply is switched when the phase difference between the substation's feed voltage and the residual voltage of the electric car is within a specified range, the power converter mounted on the electric car can maintain stable commutation without failing. You can continue driving. In particular, even if the electric car is a regenerative electric car equipped with a separately excited inverter, commutation failure does not occur in the inverter, so the reliability and safety of electric car operation are significantly improved.

(3) When an electric car passes through a section, the potential difference between the contact wires that sandwich the section can be reduced to zero, so no arc occurs in the section. Therefore, damage to the section and the pantograph of the electric vehicle due to arc generation can be avoided.

(4) Since a static semiconductor circuit breaker is used as the circuit breaker for switching the power supply, it is maintenance-free, greatly reducing the burden of maintenance and inspection, and is noiseless, significantly improving environmental friendliness.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing a conventional power supply switching method for AC electric railways, Figs. 2 to 5 show an embodiment of the present invention, Fig. 2 is a circuit diagram, and Fig. 3 is FIG. 4 is a voltage waveform diagram, and FIG. 5 is a control circuit diagram, with some of the circuits omitted. 1a, 1b, 1c, 15a, 15b...telephone line, 2a, 2b...AC substation, 3a, 3b...
Section, 5...Rail, 6...Electric car, 7
a, 7b, 7c...ground step, 11a, 11b...
...Bridge circuit, 12a-12h...Diode, 14a, 14b...Thyristor circuit breaker, 14
a', 14b'...Control circuit, 16a, 16b...Auto transformer, 21a, 21b...Voltage detector, 22
a, 22b...phase comparator, 23a, 23b...
Judgment circuit.

Claims (1)

[Claims] 1 The first AC substation to which the output voltage of the first AC substation is applied
a second contact line to which an output voltage of a second AC substation adjacent to the first AC substation is applied;
a third contact wire provided between the first and second contact wires via a section; a first semiconductor circuit breaker inserted in an electrical path connecting the first contact wire and the third contact wire; a second semiconductor circuit breaker inserted in an electric line connecting the second contact line and the third contact line, and a first phase comparison means for comparing the voltage phase of the first contact line and the voltage phase of the third contact line; a second phase comparing means for comparing the voltage phase of the second overhead contact line and the voltage phase of the third overhead contact line;
When an electric car moving from the AC substation (AC substation) to the second AC substation (or the first AC substation) moves under the third contact line, the first semiconductor circuit breaker (or the second semiconductor circuit breaker ) is turned off, and the second phase comparison means (or the first
A power supply switching method for an AC electric railway, characterized in that the second semiconductor circuit breaker (or the first semiconductor circuit breaker) is turned on when the phase difference output of the phase comparison means (phase comparison means) reaches a predetermined value.