JPS6019212B2 - Lightning arrester failure detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a failure detection device for an earth protection layer used in an electronic device having a plurality of transmission paths, such as a full-service switchboard using electronic switches in communication paths.

FIG. 1 shows a configuration in which a conventional power converter is used in a telephone line.

In the figure, 1' is a remotely installed communication line made of semiconductors, 2 is a master exchange, 3 is an overvoltage protection circuit that absorbs external surges caused by lightning, etc., and T,...Tn are terminals on the subscriber side. In the terminal equipment, a set of two subscriber lines M.・・・・・・Connected by Mn,
The darkness between the communication line 1 and the master exchange 2 is a pair of trunk lines N.
．．・・・・・・Connected with Nm. Subscriber line M.・・・
...Mn is a diode bridge DBI1...DB1n consisting of four diodes for each set, and is connected to points with different polarities of the diodes, and the point where the (1) polarity of the diodes gather is connected to the lead-in line. The points where (10) gutter characteristics are gathered are connected in series to the lead-in wire P, and the lead-in wires 0 and P are connected to the overvoltage protection circuit 3. Further, the trunk lines N, . . . . . . Similarly to Mn, they are connected to the overvoltage protection circuit 3 via diode bridges DB21 . . . DB2m and lead-in wires ○ and P. In this data circuit configuration, the subscriber line M. ...Mn or trunk line N. ...If an external surge occurs in Nm,
The surge is caused by the diode bridge DBI I...DB
1n, DB21...DB2m and lead-in line ○, P
The overvoltage protection circuit 3 absorbs the voltage through the overvoltage protection circuit 3. 0 According to the above device, compared to other conventional methods in which an overvoltage protection circuit is installed for each transmission line, ``it requires fewer overvoltage protection circuits, but the commonly installed overvoltage protection circuit becomes a hindrance.'' In this case, the scope of failure is larger, and the problem is that the failure detection function for the transmission line through subscriber line testing, etc., as in the conventional system, is not sufficient.

The present invention was made in view of the above-mentioned problems with conventional lightning protection bags, and its gist is to provide surge protection for electronic devices having multiple transmission paths by using a diode bridge and a plurality of core diodes for each transmission path. - In a power protection device that is equipped with a common overvoltage protection circuit that absorbs surges taken out from the overvoltage protection circuit, the common overvoltage protection circuit has a torrent current detector that detects the flea flow that flows into the overvoltage protection circuit. A first means for fault detection is provided, and a second means is provided for fault detection by having a current detector for the plurality of diode bridges and detecting current only for the diode bridge corresponding to a specified transmission path when necessary. There is provided a fault detection device for an earth protection layer, characterized in that it is provided with means.

Hereinafter, it will be explained in detail according to an example. Figure 2 shows an example in which the Shidenso layer equipped with the fault detection device according to the present invention is used in a telephone line. In the figure, the same oracles and numbers as in Figure 1 indicate the same parts. .

Reference numeral 4 denotes first means for monitoring the overvoltage protection circuit 3 and detecting faults, such as a common monitoring section, and reference numeral 5 indicates second means for monitoring individual diode bridges of each line and detecting faults, for example, individual monitoring sections.

First, the configuration of the overvoltage protection circuit 3 and the surge absorption process will be described.The overvoltage protection circuit 3 has circuits that are symmetrical with respect to the discharge tube date, and each circuit has a Zener diode ZD. ~ Capacitor C, Metal oxide varistor Z
N,, discharge tubes connected in parallel, diode ZD2, capacitor C2, metal oxide varistor ZN2
and a discharge tube connected in parallel, one of each connection end is connected to the lead-in wires ○ and P, respectively, and the other end is grounded to the ground G. Here, for example, subscriber line M,
When a surge voltage of (10) is generated due to lightning or the like, the surge voltage enters the lead-in line 0 through the diode DII or D2, and is dropped to the ground G through the discharge tube of the overvoltage protection circuit 3. Similarly, if surge voltage occurs in (1), the diode D13 or D14 will be discharged to the ground G through the lead-in line P and the discharge tube.The same applies if surge voltage occurs in other lines. .Overvoltage protection circuit 3
Zener diode ZD, ZD2, capacitor C,
, C2 "Noristor ZN, , ZN2 discharges the voltage due to the discharge delay until the discharge tube starts emitting to the ground G. The common monitoring section 4 is connected to the positive polarity power source Es, and the current detector D.
A circuit 41 that connects ET1, resistor R, and diode 00 in series in the forward direction and connects to the lead-in line 0 through the mechanical heating circuit.
and negative polarity power supply Es2, current detector DET2, resistor 2,
A circuit 42 in which diodes DP are connected in series in the opposite direction and connected to a drop-in line P through a mechanical contact r12, and a mechanical contact r1.
3 and resistor R3 are connected in series to form the mechanical contacts rl,, r1.
Circuit 43 connected between lead-in wires ○ and P by reversing 2.
and relay line N. . . . Diode bridge DB21 on the Nm side... Consists of mechanical contacts r16 and r17 that open and close the lead-in wires ○ and P of DB2m.

Note that the circuit 43 and mechanical contacts r16 and r17 are used during the operation of the individual monitoring section 5, which will be described later.
17 is always closed. In addition, the circuits 41 and 42 are always connected to the lead-in wires ○ and P through mechanical contacts rl and r12, but the fin pressure values of the power supplies Es and Es2 are the same as the discharge starting voltage of the overvoltage protection circuit 3 on the discharge tube date. Normally, almost no current flows through the circuits 41 and 42, and the current detectors DET1, DET2
No current is detected. Here, when a failure occurs in the overvoltage protection circuit 3, the zener diode Z with low withstand voltage
D or ZD2 becomes a short-circuit failure, and this causes a voltage to flow in the circuit 41 or 42 in the common monitoring section 4, and the current detector DETI or DET2 detects this current, and as described later, the detection signal, that is, the overvoltage Protection circuit 3
The failure information is transmitted to the master exchange 2 via another signal line (not shown). Note that the diode DO in the common monitoring unit 4
and DP are provided to prevent excessive reverse current from flowing into the circuits 41 and 42 due to surges from the drop-in wires ○ and P. Surge extraction section, that is, each diode bridge DBII to DB1n, DB21 to DB2m
The individual monitoring unit 5 that monitors the power supply Es3 and the current detector DE
A circuit 51 in which T3 are connected in series, and mechanical contacts rA, . . ., rB, . . . installed for each relay line N, .
The connecting wires 52 and 53 connected via rBm are configured so that the polarity can be reversed by mechanical contacts ri4 and r15.

For individual monitoring, when necessary, one of the diode bridges is connected to the main contact rA.・・・・・・r
Am, rB...rBm and r13, r18, r17
The selection is made by opening/closing operations of , forming a closed loop as shown in FIG. Figure 3 shows mechanical contacts rA, , as an example.
This shows the monitoring state when the diode bridge DB21 is selected by connecting rB, to the connecting lines 52 and 53, and at this time, both ends of the trunk line N, Open state at . In other words, in FIG. 3A, mechanical contact r13 is open, and mechanical contacts r14 and r15 are connected to power source E.
When the (10) side of s3 is striped to the subsequent line 53,
In this case, if the diode ○21 or D24 is short-circuited, a current flows as shown by the arrow, and the current detector DET
Detected at 3. Figure 3B shows mechanical contact r from state A.
14 and r15 are inverted, and in this case, a short circuit failure in the diode D22 or D23 is detected in the same manner as above. Figure 3C shows when the mechanical contact r13 is closed from the state shown in B. In this case, in a normal state, current flows through diode D21, resistor R3, and diode D24 as shown in the figure, but diode D21 or D24 has an open failure. No current flows, and this is detected by the current detection unit DET3. Figure 3 D shows mechanical contact r14 from state C.
, r15, an open failure of the diode D22 or ○23 is detected in the same manner as in case C above. Other diode bridge DB22 (not shown)...
...DB2m is also monitored by the aircraft when necessary, and failures are detected. Diode bridge D on subscriber line side
For fault detection of BI1...DB1n, use the fault-free diode bridge DB21...DB2m.
A trunk line N.・・・・・・Diode bridge DBI to detect fault through Nm and further through communication path Silk 1
By selecting 1...DBn and performing the operations shown in FIGS. 3A to 3D with the mechanical saddle points 16 and r17 open, it becomes possible to detect a fault on the master exchange 2 side.

In addition, diode IJ Tsuji DBI 1...DB1
The mechanical contacts r16 and r17 may remain closed when detecting a short-circuit failure of the diode n. Figure 4 shows the current detector D used in this example using a photocoupler.
In one circuit example of ETI to DET3, a resistor RP is connected in parallel to the input terminals P, P2 of the photocoupler PC, and the output terminal is connected to a power source E and a load resistor Rx, and has an output terminal X. .

The input terminals P, , P2 are connected in series in a circuit that is to detect current, and when a current flows from terminal P2 to P, the light emitting diode in the photocoupler PC emits light, and the light is transmitted to the photocoupler on the output side. The diode senses the signal and outputs a signal to the output terminal X, and the output signal is sent to the master exchange 2. As explained above, in this embodiment, the common monitoring unit is installed in the earth protection layer consisting of the conventional diode bridges DB11 to DB1n, DB21 to DB2m, the overvoltage protection circuit 3 and the lead-in wires 0 and P, without using any special parts. 4 and an individual monitoring section 5, the common overvoltage protection circuit 3 can always detect faults without damaging the communication path function, and for each diode bridge, the trunk line or the transmission line of the subscriber line can be selected. By doing so, it is possible to detect a fault when necessary, so that the faulty line can be confirmed at the master exchange 2.

As described above, according to the present invention, surge protection for an electronic device having a plurality of transmission lines includes a diode bridge for each transmission line and a common overvoltage protection circuit that absorbs surges extracted from the plurality of diode bridges. In the above-mentioned common overvoltage protection circuit, the common overvoltage protection circuit is provided with a first means that has a current detector and detects the current flowing through the overvoltage protection circuit to detect a fault, and the plurality of diode bridges are provided with A second means of fault detection by detecting current only for the diode bridge corresponding to the specified transmission path when necessary is provided, which has a current detector, so faults in the common overvoltage protection circuit can be detected immediately. Of course, this method has the advantage that the location of the diode bridge in the transmission line that has caused the failure can be immediately identified.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and Fig. 1 shows a configuration diagram when a conventional earth protection layer is used in a telephone line, and Fig. 2 shows an earth escape system equipped with a current detection device according to the present invention. FIG. 3 is a diagram showing the connection state of the diode bridge DB21 when a fault is detected, and FIG. 4 is a circuit diagram showing a specific example of the current detector. 1... Call line silk, 2... Master station exchange, 3...
Overvoltage protection circuit, 4...Common monitoring section, 5...Individual monitoring section, DBI I~DB1n, DB21~DB2m...
...Diode bridge "M, ~Mn..."
Subscriber line, N, ~Nm... Trunk line, 0. P…・
... Drop-in line, T, ~Tn... ...Terminal device. Figure 1 Figure 2 Figure 4 Figure 3

Claims (1)

[Claims] 1. In a lightning arrester equipped with a diode bridge for each transmission line and a common overvoltage protection circuit that absorbs surges taken out from the plurality of diode bridges as surge protection for an electronic device having a plurality of transmission lines, the above-mentioned lightning arrester is provided. The common overvoltage protection circuit has a current detector and a first means for detecting a fault by detecting the current flowing through the overvoltage protection circuit. A failure detection device for a lightning arrester, characterized in that a second means is provided for detecting a failure by detecting current only for a diode bridge corresponding to a designated transmission path.