JPH0777856B2 - Relaying method for protection against contact with different frequencies of AC feeding circuit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective relay method for an alternating current feeding circuit of an electric railway passing through a different frequency power supply section when different frequencies are touched in the alternating current feeding circuit. It is about.

Conventional technology The frequency of Japanese electric power companies is 60 Hz in the west and 50 Hz in the east, with Fuji and Itoigawa as the boundaries. Therefore, when traveling across both of these sections, there will be mixed feeder circuits using two different frequency substations as power sources. Therefore, as shown in FIG. 3, a feeder section 25 is provided in such an AC feeder circuit as a butt portion of feeder wires 23, 24 of different frequency power sources 21, 22 having different rated frequencies. The feeder section 25 is provided on the feeder circuit with a switching section S which can be insulated from the feeder 23 by the switch 26 and the insulating portion 27 and can be insulated from the feeder 24 by the switch 28 and the insulating portion 29. Switch when train A is on track of feeder cable 23
26 is closed and switch 28 is open to power switching section S
When the train A enters the switching section S by applying the voltage from the switch 21, the switch 26 is opened first, and then the switch 28 is closed after about 300 ms, and the voltage from the power source 22 is applied to the switching section S. ing. In addition, train A gaki electric wire 24
Similarly, the voltage applied to the switching section S from the power source 22 to the power source 21
Switch to the one by.

Problems to be Solved by the Invention However, in the case where the feeders of the different frequency power source are butted as described above, contact of different frequencies may occur for some reason. In the case of the feeder section 25, contact of different frequencies occurs due to failure of the switches 26 and 28 or short circuit of the insulating portions 27 and 29. FIG. 4 shows a simplified equivalent circuit in the case where the alternating current feeding circuit is touched by the above-mentioned causes. In FIG. 4, when the frequency of the power source 21 is 50 Hz and the frequency of the power source 22 is 60 Hz, The power supply voltage is expressed as V1 = Emsin (2π ・ 50t) on the power supply 21 side and V2 = Emsin (2π ・ 60t) on the power supply 22 side. R1 and R2 indicate the resistance of each feeder 23 and 24, and L1 and L2 indicate the inductance. Therefore, the impedance of this circuit is Z50 = R1 + R2 + j2π ・ 50 (L1 + L2) when the frequency is 60Hz. In this case, Z60 = R1 + R2 + j2π · 60 (L1 + L2). Therefore, when the feeder wires 23, 24 are short-circuited due to the failure of the switches 26, 28 as described above and contact of different frequencies occurs, the switch SW in FIG. A current I corresponding to the current difference between the power supplies 21 and 22 flows as shown in the equation.

If Z50≈Z60 = Z, then Therefore, as shown in FIG. 5, a current I having a maximum amplitude of 2 Em / Z and a waveform of 55 Hz and having an amplitude of 0.5 Hz flows at intervals of 0.1 seconds. If such an excessive and unstable current flows, the train and other parts will be seriously damaged. Therefore, it is necessary to quickly protect the AC feeding circuit when touching different frequencies.

The simplest method of protecting the AC feeder circuit when touching different frequencies is to simply detect the rated frequency component of the power source in another place contained in the power supply current, and set the set value in the rated frequency component of the power source in another place. If it exceeds the limit, the method of shutting off the power supply at its own place can be considered. However, the above method has the following problems. That is, in order to detect the rated frequency component of the power source elsewhere, a bandpass filter having that frequency as the center frequency must be provided in front of the detector, but due to the characteristics of the bandpass filter, it has a certain extent in the passband. , The frequency component on the local power supply side is passed through to some extent. In this case, there is no problem if the current on the local power supply side is small, but the component that has passed through the bandpass filter due to a large value of the current on the local power supply side, such as a short-circuit accident on the feeder line, has a predetermined value. If the set value is exceeded, there is a disadvantage that it is determined that different frequency contact has occurred and an erroneous failure location is searched for even though different frequency contact has not occurred. Also,
Even if the load current is large, the circuit breaker may operate unnecessarily due to different frequency contact.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method capable of reliably protecting an AC feeding circuit only when different frequencies are touched.

Means for Solving the Problems In order to achieve the above object, the present invention detects the power supply current of an alternating current feeder circuit having a butting portion of feeder wires of different frequency power supplies, and detects this detected current as the rating of its own power supply. Separate the frequency component from the rated frequency component of the power source in another place, suppress the rated frequency component of the local power source, and use the rated frequency component of the power source in another place as the operating element. It is characterized in that when the difference becomes a predetermined value or more, the local power source is shut off.

Examples Hereinafter, the present invention will be described in detail based on illustrated examples.

FIG. 1 is a block circuit diagram for carrying out a method for protecting against contact with different frequencies of an AC feeder circuit according to the present invention, in which 1 is a power source with a rated frequency of 50 Hz, 2 is a feeder line for the power source 1,
3 is a circuit breaker provided on the feeder line 2. Although not shown, on the extension of the feeder line 2, a butt portion with the other feeder line having a rated frequency of 60 Hz is provided in the same manner as the feeder section 25 shown in FIG.

Reference numeral 4 is a current transformer, which is configured to supply the current flowing through the feeder 2 with an I / N (N
Is detected arbitrarily, and this detected current is converted into a voltage signal by the current-voltage converter 5. 6 is a different frequency rectifier circuit, and 7 is a rated frequency rectifier circuit. The different frequency rectifier circuit 6 rectifies a band pass filter 8 having a center frequency of 60 Hz which is the rated frequency of a power source elsewhere and an AC signal passing through this filter. Rectifying circuit 9 for
The rated frequency rectifier circuit 7 is composed of a bandpass filter 10 having a center frequency of 50 Hz which is the rated frequency of the power source on the feeder 2 side for detecting current, and a rectifier circuit 11 for rectifying an AC signal that has passed through this filter. . FIG. 2 shows the characteristics of the bandpass filters 8 and 10. F1 is a characteristic curve showing the pass band of the band pass filter 8 and F2 is a characteristic curve showing the pass band of the band pass filter 10. Therefore, the output of the current-voltage converter 5 is separated into the 60 Hz component and the 50 Hz component by the band pass filters 8 and 10. Here, assuming that the 60Hz component is E1 and the 50Hz component is E2 when contact of different frequencies occurs, the components E1 and E2 are the same voltage when the characteristics of the bandpass filters 8 and 10 are the same as shown in FIG. It becomes a value. The 60 Hz component E1 becomes an operating element that cuts off the feeder line 2, and the 50 Hz component E2 is attenuated by the attenuator 12 and becomes a suppressing element E2 '. The attenuator 12 is used to cause the operating element E1 to exceed the suppressing element E2 'when different frequencies are touched. Therefore, the attenuator 12 can be omitted by using two bandpass filters 8 and 10 having different characteristics.

13 is an overcurrent detector, which is 60 Hz from the different frequency rectification circuit 6
The component E1 is input, and when this input value exceeds a predetermined set value, an ON signal is issued to one terminal of the AND circuit 14.

Reference numeral 15 denotes a comparator, which sets the operating element E1 to the + side and suppresses the element E1.
When 2'is input to the-side and the operating element E1 exceeds
An ON signal is issued to one input terminal of the circuit 14.

As described above, according to the above configuration, when contact of different frequencies occurs, the circuit breaker 3 operates to shut off the feeder line 2. However, in addition to contact of different frequencies, for example, a ground fault of the feeder line 2, etc. In the event of a large current with a rated frequency of 50 Hz flowing through the feeder circuit on the detection side, the circuit breaker 3 is reliably prevented from operating. The reason is that the circuit breaker 3 is configured to operate only when the operating element E1 reaches the set value or more and the difference between the operating element E1 and the suppressing element E2 'becomes the predetermined value or more. . The reason for this is described in detail below.
That is, the pass band of the band pass filter 8 has a certain extent of widening as shown in FIG. 2 and some 50 Hz components also pass through. Therefore, for example, when a short circuit accident occurs in the feeder 2 of 50 Hz, an extremely large short circuit current is generated. Due to this, the magnitude of the 50 Hz component detected through the bandpass filter 8 may exceed the set value of the excessive motion element detector 13.
For this reason, the excessive motion element detector 13 outputs a detection signal to open the gate of the AND circuit 14 although the contact of different frequencies is not caused. However, in the case of a short-circuit accident of the electric wire 2 which is different from touching of different frequencies, the suppression element always has a larger value than the operation element, so that the comparator 15 does not output the comparison output, and therefore the AND circuit 14 outputs the operation signal. As a result, the circuit breaker 3 does not operate. Therefore, the AND circuit 14 outputs the relay 16 from the output terminal when the operating element E1 reaches the set value or more and the operating element E1 exceeds the suppressing element E2 '.
Emits a signal to operate.

The relay 16 controls the circuit breaker 3, and when an operation signal is input from the AND circuit 14, sends a break command to the circuit breaker 3, and the feeder 2 is cut by this command.

Although the method of the present invention is applied to the feeder of 50 Hz in the above embodiment, the method of the present invention can be applied to the feeder of 60 Hz. In this case, the 60Hz component is the suppression factor, 50
The Hz component is the operating element.

Further, the present invention can be applied to any AC feeding circuit having butt portions of feeder wires having different rated frequencies, regardless of the value of the rated frequency.

EFFECTS OF THE INVENTION As is apparent from the above description, according to the method for protecting against different frequency contact of the AC feeding circuit according to the present invention, the circuit breaker is not operated only by the frequency component of the power source of another place which is an operating element, When the rated frequency component of the power source reaches or exceeds the set value and the difference between the rated frequency component of the power source elsewhere and the prescribed frequency component of the local power source exceeds the prescribed value, the circuit breaker is operated. Since the rated frequency component of the local power supply becomes excessive, the circuit breaker does not operate even if the operating element exceeds a predetermined value, and therefore the circuit breaker does not operate unnecessarily due to causes other than touching of different frequencies. In addition, if the operating element is equal to or greater than the set value and the difference from the suppression element is equal to or greater than the predetermined value, the circuit breaker will operate reliably, so if an interfering frequency of different frequencies occurs, protect the AC feeding circuit promptly. You can do it.

[Brief description of drawings]

FIG. 1 is a block circuit diagram for carrying out the method of the present invention, FIG. 2 is a detection waveform diagram by a bandpass filter, FIG. 3 is an AC feeding circuit diagram having a butting portion of different frequency power supplies, and FIG. FIG. 3 is a simplified equivalent circuit diagram, and FIG. 5 is a waveform diagram when different frequencies are touched.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Norio Suto 8-12-6 Kitamachi, Nerima-ku, Tokyo (72) Inventor Mitsuru Takano 62-1 Emen, Kuki City, Saitama Prefecture (72) Hironori Hamada Funabashi City, Chiba Prefecture Narashinodai 4-34-21 A401 (72) Inventor Kukichi Uchida 4-4 10 Segawa, Minoh City, Osaka Prefecture Tsuda Denki Keiki Co., Ltd. (72) Inoue Hisao Araki 4-4 Segawa, Minoh City, Osaka Prefecture No. Tsuda Denki Keiki Co., Ltd. (72) Inventor Tetsuzo Kitagawa No. 4-10 Segawa, Minoh City, Osaka Prefecture Tsuda Denki Keiki Co., Ltd.

Claims (1)

[Claims] 1. A power source current of an AC feeding circuit having a butting portion of feeder lines of a different frequency power source is detected, and the detected current is separated into a rated frequency component of a local power source and a rated frequency component of another power source, When the rated frequency component of the local power source is the suppression element and the rated frequency component of the other power source is the operating element, and the operating element reaches the set value or more and the difference between the operating element and the suppressing element becomes the predetermined value or more, A relaying method for protecting against contact with different frequencies of an AC feeder circuit, which is characterized by cutting off the feeder wire of the power supply.