JP3282897B2 - Live line detector of DC train line - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a live line detector for detecting a live state of a DC train line in an electric substation.

[0002]

2. Description of the Related Art FIG. 5 is an explanatory diagram showing a method of supplying power to a DC train line. That is, in order to run the DC train, first, at the A substation (denoted as A-SS in the figure), the electric power supplied from the power company through the transmission line 51 (about several thousand kVA to ten thousand thousand kVA). , Which is different in each substation), and the voltage is reduced from the transformer 52 to 1200 V, and furthermore, the three-phase bridge-connected full-wave rectifier 53 provides six phases (12 in some cases). Phase) full-wave rectification, bus (busbar)
A DC voltage of 1500 V is applied to 54. Then, bus 54 → feeder line 55 → train line 56 → pantograph 5
7 → train 58 (power system / others) → travel rail 59 → return line 60 (indicated by a broken line in the figure), thereby forming a DC feeding circuit which is a loop circuit reaching the negative electrode of the rectifier 53. The train 58 can run.

The train line 56 is a DC train line (an electric line provided to supply DC power to a current collector of a train).
In each of the substations of the train 58, the substations are separated via an air section 61 at intervals of 4 to 10 km. Then, to each of the train lines 56 isolated by the air section 61, power of 1500 V DC is simultaneously supplied from an adjacent B substation (denoted as B-SS in the figure) by a parallel feeding system. It is supposed to be.

[0004] On the other hand, in the direct current feeder circuit, when feeding power from the bus 54 to the electric train line 56, four feeder lines (12 in some cases) are usually used. ing. Here, as the feeder lead 55, for example, a copper plate having a width of 100 mm and a thickness of 8 to 10 mm is used in a bare state. A high-speed circuit breaker (H
SCB). When checking or repairing the electric line 56, the DC feeder circuit is cut by the high-speed circuit breaker, and the electric line 56 is set in a non-power supply state.

The high-speed circuit breaker is controlled by remote control from a control center (not shown). However, in order to further enhance safety, the high-speed circuit breaker is controlled separately from the control center. Whether the power is actually supplied, that is, the live state of the electric line 56 is detected in parallel. In detecting such a live state, a detection unit is directly attached to an arbitrary position of the feeder lead 55 located on the exit side of the high-speed circuit breaker, and a contact type measuring the voltage of the feeder lead 55 is performed. Using a detection device or a surface potential sensor (a sensor that converts the electric field intensity into a DC voltage using the vibration amplitude of a mechanical oscillator), a non-contact detection device that measures the surface electric field intensity of the feeder lead 55 For this detection device, see Jpn.
313328) and the like.

Therefore, in the parallel feeding system, an abnormal state occurs in which the high-speed circuit breaker of either the A substation or the B substation does not disconnect the DC feeding circuit for some reason. However, if these hot-line state detecting devices are used, the hot-line state of the DC electric line can be immediately known, so that the safety in inspecting and repairing the electric line 56 is ensured.

[0007]

However, when the above-mentioned plate-shaped member is used as the feeder lead 55, flexibility is inevitably lacked in performing various wirings in the substation. become. This leads to a restriction in securing an installation space for the detection device installed to measure the voltage of the feeder lead 55. Therefore, recently, a feeder lead 55 of a plate-like body has been used.
Instead, flexible cable lines have been frequently used. As such a cable, for example, a bundle of several cables in which a core is coated with an insulator such as cross-linked polyethylene and coated with polyvinyl chloride or the like is used.

However, when such a cable line is used, the above-mentioned contact-type hot-line state detecting device cannot be used because the detecting portion cannot be brought into contact with the bare conductor of the feeder line. I can't. On the other hand, the above-mentioned non-contact type live-line state detection device can measure the electric field strength, that is, the potential of the conductor, in the case of a plate-shaped bare conductor, but in the case of a cable, the electric field is measured by a covering insulator. Disturbed, unable to measure the line voltage accurately.

The present invention has been made in view of the above-mentioned situation, and is a live line capable of extremely easily detecting the live state of a DC train line without being affected by the wiring conditions in a substation for electric railways. It is intended to provide a detector.

[0010]

In order to achieve the above object, the present invention relates to a live-line detector for detecting a live state of a DC trolley line, which rectifies a DC voltage supplied to the DC trolley line. It is characterized by comprising a coupling capacitor for extracting the ripple component, and a feeding determining means for determining that the DC power line is fed when the rectified ripple voltage is extracted by the coupling capacitor.

[0011] Further, the present invention provides that, when the DC train line is a cable line covered with an insulator, the coupling capacitor comprises the cable line and a metal wrapping provided on the peripheral surface thereof. It is characterized by being formed.

[0012]

According to the above configuration, by the coupling capacitor,
The rectified ripple component of the DC voltage fed to the DC train line is extracted. Here, when the DC train line is a cable line covered with an insulator, a metal winding body is wound around the peripheral surface of the cable line, and the cable line and the metal winding line are wound. A coupling capacitor is formed from the body. When the rectified ripple voltage is extracted through the coupling capacitor, the feeding determining means determines that the DC power line is fed. In this manner, the live state of the DC train line is reliably detected.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a circuit diagram showing an example in which a live-line detector according to the present invention is applied to a feeder circuit of a DC train line, and FIG. 2 shows an appearance of a detection unit 10 of the live-line detector shown in FIG. It is a perspective view. Note that the entire configuration of the feeder circuit of the DC train line is described in detail in FIG. 5, and thus, here, only the relevant portions of the DC feeder circuit to which the present live line detector is applied are simply shown. ing.

The live-line detector includes a main body 1 (having an internal circuit configuration surrounded by a two-dot chain line in the figure) and a detecting section 10. Then, in the DC feeder circuit shown in FIG. 1, between the rectifier 2 (having an internal configuration surrounded by a broken line in the figure) → the circuit breaker 3 → the disconnector 4 → the feeder lead line 5 → the train line 6. In the above, by directly attaching the detection unit 10 to the feeding line 5 located on the output side of the disconnector 4,
The live state is detected.

As shown in FIG. 2, for example, three single-core cross-linked polyethylene power cables 20 are bundled and used as the feeder lead wire 5. In addition, the detection unit 10
It is configured by engaging two aluminum engagement members 11 and 12 which are curved and formed so as to be in close contact with the peripheral surface of the cable wire 20. Flanges 13 to 16 serving as engagement fastening portions are formed on both sides of both engagement bodies 11 and 12, and are formed by bolts, nuts, screws, or the like.
It is possible to fix it firmly. A lead wire 17 is attached from the surface of the contract body 11 (or 12) to connect the detection unit 10 and the main unit 1. Here, when power is supplied to the cable 20, a coupling capacitor is formed between the detection unit 10 and the cable 20. That is, a coupling capacitor is formed in which the detecting section 10 and the bare conductor of the cable 20 are used as the bipolar plates, and the respective coating layers of cross-linked polyethylene and vinyl chloride are inserted as dielectrics.

On the other hand, the rectifier 2 shown in FIG. 1 uses a three-phase bridge-connected full-wave rectifier, and its output voltage always includes a ripple component. In FIG. 1, in order to show this, the rectifier 2 is expressed as a voltage output combining the DC component and the AC component (ripple component).
The ripple voltage output at the time of feeding is, for example, 300 Hz in the case of the output of the six-phase full-wave rectifier provided at both the adjacent substations A and B in the parallel feeding system.
About 5% at (50 Hz x 6) (1500 x 0.05 =
75V).

Here, the ripple voltage of the cable line 20 can be extracted by a coupling capacitor formed by the detection unit 10 and the cable line 20. Therefore, the ripple component extracted from the detection unit 10 is taken into the main unit 1 through the lead wire 17 and the presence or absence of the ripple voltage is detected, whereby the feeder lead wire 5 is detected.
Thus, the live state of the DC train line can be detected.

In the main unit 1, the ripple voltage extracted by the detection unit 10 is input to the input unit I (a resistor R is connected in series,
The capacitor C is connected in parallel), amplified by an amplifier AMP, passed through a high-pass filter HPF,
It is rectified by the rectifier D. Further, after passing through the ripple meter V (which is a voltmeter), the comparator COMP determines whether or not the voltage is a ripple voltage in the case of normal feeding. If it is determined that the voltage is the ripple voltage in the case of normal feeding, the transistor T sets the relay _RY.
Is operated so that the LED emits light and the output can be taken out through the output unit E.

Here, as the high-pass filter HPF, a filter corresponding to the frequency of the input ripple voltage is used, and the detection of the ripple voltage is facilitated. In addition, in order to operate this live-line detector, ±
A constant voltage of 15 V and 0 V is supplied to each functional block. FIG. 7 is a ripple voltage in which the output voltage P of the rectifier D is recorded as the actually measured value in FIG. In the figure, T is a time zone in which the feeding to the DC train line is stopped, and T is a time zone in which feeding is performed. In this way, by monitoring the ripple voltage, it is possible to clearly determine whether or not a feeding is occurring.

FIG. 3 is a schematic diagram showing an example of a cable line for calculating the capacitance of the coupling capacitor shown in FIG.
For example, when the cross-sectional area of the cable 20 is 325 mm ² , the core wire (bare conductor) starts from the center of the cable 20.
Is 10.5 mm, and the distance b to the peripheral surface position of the crosslinked polyethylene coating layer is 14 mm.
Similarly, the distance c to the peripheral surface position of the outermost PVC layer is 17 mm. The relative permittivity K ₁ of the crosslinked polyethylene is 2.3, the relative permittivity K ₂ of polyvinyl chloride is 7, and the vacuum permittivity ε ₀ is 10 ⁷ / 4πc ^2.
≒ 1 / (36π × 10 ⁹ ) (c is the light speed = 2.9997)
Assuming 3 × 10 ⁸ m / s), the capacitance C [F / m] of the cable 20 at this time is calculated by the following equation.

[0021] _{C = 2πε 0 / {(1} / K 2) l n c / b + (1 / K 1) l n b / a} Substituting the values described above into the above equation, C = {2π × 1 /
(36π × 10 ⁹ ) × 10 ¹² ｝ / ｛(1/7) × l _n 1
7/14 + (1 / 2.3) × 1 _n 14 / 10.5｝ ≒ 3
63 [pF / m]. Accordingly, the value of the capacitance C of the coupling capacitor when the length L in the line direction of the detection unit 10 provided on the peripheral surface of the cable wire 20 is 15 cm is as follows.

C = {363 [pF / m] / 100 cm} × 15 cm = 54.45 [pF] That is, 15 cm is applied to the cable 20 having a sectional area of 325 mm ^2.
When the width detecting section 10 is formed, a coupling capacitor having a capacitance of about 54 [pF] is formed. FIG. 4 is a table showing actual measurement results of the capacitance of each coupling capacitor formed by changing the shape according to the number of core wires of the cable wires. The measurement conditions were as follows: temperature 20 ° C, humidity 6
The measurement was performed at 2% and a measurement frequency of 1 kHz. As shown in the middle part of the drawing, an aluminum foil was used
so that it is in contact with a bundle of cable lines of the m ² circumferential surface, and was varied in the linear direction length L in 10~25cm measuring the capacitance of each case.

As shown in the upper part of the drawing, reference numeral (A) denotes a cross-sectional shape in the case of one core, reference numeral (B) denotes a cross-sectional shape in the case of two cores, and reference numeral (C) denotes a cross-section. The cross-sectional shape when the number of the cores is three, the symbol (D) is the cross-section when the number of the cores is three and one of them is one vinyl pipe,
Reference numeral (E) similarly indicates a cross-sectional shape when the number of cores is four. In the figure, the portion with fine horizontal stripes is a cable including a conductor portion and a covering insulator which are core portions,
The line surrounding the conductor indicates an aluminum foil. The coupling capacitor formed in this manner has a very high dielectric strength structurally, and it is considered that a dielectric breakdown failure is inevitable.

Next, as is clear from the table (actual measurement results) shown in the lower part of the figure, as L increases from 10 to 25 cm, the capacitance of the coupling capacitor increases. Also, the capacitance increases as the number of core wires increases from 1 to 4. Further, the capacitance is larger in the case of the three triangles indicated by the symbol (C) than in the case of the three squares indicated by the symbol (D). From these results, it is understood that the capacitance of the coupling capacitor increases as the area of the detection unit 10 as an electrode plate increases. Also, it can be seen that the measured value of the same capacitance when L = 15 cm in the code (A) is 67 pF, which is close to the value 54 pF calculated in FIG. Further, when considering the actual wiring of the cable line, it is considered that the length L in the line direction of the detection unit 10 is preferably about 15 cm. Therefore, after all, the coupling capacitor formed on the cable line is an electrostatic capacitor. It is only necessary to form a capacitor having a capacitance of about 67 to 119 pF.

In the above-described embodiment, the detecting portion 10 is configured such that the peripheral surface of the cable wire is wound with a metal conductor (in the embodiment, an aluminum-made winding body). It is also possible to take out the ripple voltage by using a ready-made coupling capacitor in a place where the main circuit is not affected by the breakdown of the coupling capacitor, for example, by using other DC equipment. A device having a withstand voltage performance (for example, an impulse of 65 kV) that is about three times or more than that of the above-mentioned device is used. Of about 250 pF is used.

Also, when a copper plate (B) shown in FIG. 6 is used as a feeder lead as in the prior art, the periphery of the copper plate is kept in a non-contact state. An aluminum frame body disposed so as to be closely enclosed is used as an electrode plate (P1), or is arranged so as to be in close contact with both plate-like surfaces of the copper plate-like body in a non-contact state. A U-shaped aluminum plate is provided as an electrode plate (P
2) As a result, a coupling capacitor having a predetermined capacitance can be formed. Therefore, even in such a case, it is possible to take out the ripple voltage by using the live-line detector according to the present invention and reliably detect the live-line state of the feeder lead.

[0027]

According to the present invention described above, by providing a coupling capacitor to a feeder lead wire or the like, it is possible to extract a ripple of the DC voltage fed to the DC train line. Then, when the ripple voltage is extracted by the coupling capacitor, the feeding determining means immediately determines that the DC power line is fed. Therefore, it is possible to reliably detect the live state of the DC train line.

Further, when a cable line is used as a feeder lead-out line in a railway substation due to wiring restrictions, the live-line detector according to the present invention is used to change the live-line state. The detection can be performed very easily and reliably. Therefore, when using the parallel feeding method, even if an abnormal state occurs in which the DC feeding circuit is not disconnected for some reason, it becomes possible to immediately recognize this, and the safety is reduced. Sufficiently secured.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an example in which a live line detector according to the present invention is applied to a feeder circuit of a DC electric line.

FIG. 2 is a perspective view showing an appearance of a detection unit 10 of the live-line detector shown in FIG.

FIG. 3 is a schematic diagram illustrating an example of a cable line for calculating the capacitance of the coupling capacitor illustrated in FIG. 2;

FIG. 4 is a table showing actual measurement results of the capacitance of each coupling capacitor formed by changing the shape in accordance with the number of cable cores;

FIG. 5 is an explanatory diagram showing a method of supplying power to a DC train line.

FIG. 6 is a schematic view showing an example of obtaining a coupling capacitor in the case of a copper plate.

FIG. 7 is an example of a measured waveform of a ripple voltage.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main part of live-line detector 2 Rectifier 3 Circuit breaker 4 Disconnector 5 Feeder lead 6 Train line 10 Detection part of live-line detector

Continuation of the front page (72) Inventor Yoshinao Nakata 4-4-1-10 Segawa, Minoh-shi, Osaka Tsuda Denki Keiki Co., Ltd. (56) References JP-A-61-14576 (JP, A) JP-A-58-77667 (JP, A) JP-A-63-106570 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02H 3/50 G01R 19/155

Claims (2)

(57) [Claims] 1. A live-line detector for detecting a live state of a DC train line, comprising: a coupling capacitor for extracting a rectified ripple component of a DC voltage supplied to the DC train line; A live-line detector, comprising: a feeder determining unit that determines that the DC train line has been fed when being taken out. 2. When the DC train line is a cable line covered with an insulator, the coupling capacitor is formed of the cable line and a metal wrapping provided on a peripheral surface thereof. The live-line detector according to claim 1, wherein: