JPS6016130Y2 - Two-wire information transmission device with fault detection device - Google Patents

Description

[Detailed Description of the Invention] The present invention is a two-wire information transmission line for wired broadcasting, telephone communication, etc. when a disconnection or short-circuit failure occurs in the transmission line.
This invention relates to a two-wire information transmission device equipped with a failure detection device that can quickly and efficiently detect a failure even while information is being transmitted.

A device that detects disconnections, short circuits, or poor insulation (damage to insulators, damage and deterioration of coatings, etc.) in conventional two-wire wired broadcasting lines, telephone lines, and other transmission lines, as well as abnormal disturbances due to the connection of pseudo equipment. It is not possible to detect an abnormality during the transmission of information or during the transmission time. For example, if a computer line is currently unable to send or receive data (disconnection or crosstalk), the failure will be discovered only after the next handling occurs. In addition, although it is rare, a pseudo device is connected in the middle of the transmission line, and even if wiretapping or money fraud is carried out, it is impossible to detect and is extremely inconvenient.Furthermore, when making measurements, troubleshooters must repair the transmission line each time. Detection is not possible unless you go to the terminal and short-circuit the terminal and the conductor, or connect the equipment and the transmission line, and it takes a lot of time to perform measurements, especially during bad weather or storms. This is not an easy task, and the transmission of information such as communication or broadcasting must be interrupted during that time, so in case of an emergency, necessary information cannot be sent, resulting in great damage.

In addition, recently, transmission lines for cable broadcasting have been installed in various cities, towns, villages, and agricultural cooperatives for public announcements and emergency communications. It is sometimes used for centralized meter reading of usage, but for example, when the usage of propane gas, etc. of customers in remote areas is measured at a management center, and when supply and demand is centrally managed, it is necessary to detect the occurrence of a failure. There was a risk that the supply of propane gas, etc., would not be available in time when it was needed.

This invention is designed to prevent the transmission of signals from information sources such as broadcasters at the end of a two-wire transmission line so that the administrator can know whether there is a problem or not, even during broadcasting, while being present at the management office. An inductance element is connected so that there is no interference, and when a DC current is passed through the transmission line and a fault occurs, differential relays, Wheatstone bridges, differential voltage comparators, and other response means are activated in response to changes in the DC current. The response of the response means operates an alarm lamp, an alarm buzzer, an alarm bell, or other fault detection device, and a filter is provided to prevent the energy of the information source from flowing into the response means, and the information source is connected to the transmission path. It is connected.

This will be explained below along with examples.

FIG. 1 shows an example in which differential relays are mainly used as response means for responding to changes in direct current flowing through a transmission line when a fault occurs.

As is well known, the transmission line 8 is sequentially connected to a receiving device 9 of each customer, and an inductance element 1 having an impedance sufficient to block the transmitted signal is connected to the terminal end of the transmission line 8.

This inductance element uses a blocked wire ring in which a conducting wire is wound around a core made of iron, silicon steel plate, permalloy, ferrite, or other magnetic material, and an inductance of 2 [H] or more is usually sufficient. , may be increased or decreased as appropriate depending on the transmission path and other various conditions.

The sending end of the transmission line is the common contacts 2a and 2b of the interlocking switching means 2.
Various contacts are provided corresponding to this common contact, and in the figure, contact T is connected to a telephone line, etc., contact B is connected to a broadcaster 7, and can be used for other purposes such as centralized meter reading. Other contacts may be connected.

The relay 3 used as a response means has a main winding Wa and an auxiliary winding wb, and the main winding and the auxiliary winding are made of the same wire with the same number of turns, or the main winding is made of a thick wire to increase the withstand current. Sometimes it is wrapped in paper.

One of the main windings Wa is connected to the transmission line, and the other, together with one of the auxiliary windings wb, is connected to a terminal of the power source Ea.

The other of the auxiliary windings is connected to the common contact 2b of the interlock switching means 2 via a rheostat R.

The alarm lamp 4, the alarm buzzer 6, the alarm bell, and other fault detection devices are connected so that the voltage of the power source Eb is supplied to the detection devices through the contacts of the relay.

Further, the alarm buzzer, alarm bell, etc. are further connected so that the above voltage is supplied through the switch 5, and the operation of the above-mentioned buzzer, bell, etc. can be stopped by this switch.

Since a blocking wire is connected to the end of the transmission line, the transmission line acts almost as if it were open for information signals from broadcasting equipment, telephones, computers, etc., and the energy of the information signal is lost. Transmission and reception can be performed without any electrical interference and without any adverse electrical effects on the transmission path.

In this state, two circulating currents flow from the power tank a to the transmission line and the main winding Wa, and on the other hand, a magnetic flux is generated in the auxiliary winding wb in a direction that cancels the magnetic flux generated by the current flowing to the main winding. Another circulating current flows, and the magnitude of this current is adjusted by the rheostat R so that the relay 3 does not operate during normal times when there is no back injury.

1 In the above device which is normally in such a state, if a disconnection fault occurs in the transmission line, current will no longer flow through the main winding Wa, so the relay 3 will operate only with the current flowing through the auxiliary winding wb and detect the fault. The occurrence of a failure can be determined by the movement of the tool.

When a short circuit fault occurs, the DC resistance of the transmission line decreases, so the current flowing through the main winding Wa increases from the normal current,
This overcomes the current flowing through the auxiliary winding and the relay 3 operates.

In any of the above cases, the relay operates to cause a mechanical change, that is, its contacts close, so that the fault detector operates and it is possible to know that a fault has occurred.

As described above, if the rheostat R is adjusted to prevent the relay from operating during normal times, the administrator can easily know whether there is a failure at any time from the office and immediately begin recovery work. I can do it.

Although it is rare, even if a pseudo device is installed in the middle of a transmission line, an abnormality is immediately discovered due to an imbalance between the rheostat R and the transmission line.

In addition, relay 3 is installed so that the presence or absence of a failure can be monitored 24/7 while the response means is connected to the transmission line even when the information signal is being transmitted.
A filter is provided between the transmission line and the transmission line, and in the one shown in the figure, a low-pass filter consisting of a blockage wire ring 10 and a capacitor C is provided.

Since the energy of the information signal from the broadcasting machine or telephone line is blocked by the above-mentioned low-pass filter, it can be transmitted to each customer without waste without flowing into the relay 3 side, and if a problem occurs even during broadcasting, an alarm buzzer is immediately sounded. , fault detection devices such as alarm lamps operate to indicate the fault.

Furthermore, if the current flowing into or out of the power supply Ea or the current flowing through the main winding Wa is detected by an ammeter, this will decrease or become zero in the event of a disconnection fault compared to the normal current value, and will increase in the event of a short circuit fault. The mode of failure can also be identified from the indicated value of the ammeter.

FIG. 2 shows an example in which a Wheatstone bridge with one side of the direct current resistance of the transmission line is used as the response means.

The Wheatstone bridge contains a circulating current that originates from the electrolyte building a and returns to the power supply Ea through the transmission line and the resistance between S and X, and a circulating current that originates from the power supply Ea and passes through the resistance between rheostat R and VX. Then another circulating current is formed which returns to the electric current a.

Then, a DC power source Ea is connected between X and V in the figure, to one side between the opposing connections on each side of the Wheatstone bridge.
On the other hand, in the figure, a relay 13 is connected between S and V via a rectifying element 11, and another relay 14 is connected via another rectifying element 12 that is oriented in the opposite direction to this rectifying element. .

During normal times, the rheostat R is adjusted to balance the bridge so that both the relays 13 and 14 that operate the fault detectors do not operate.

When a disconnection fault occurs in the transmission line, if the power supply Ea has the polarity shown in the figure, the circulating current flowing through the transmission line will be cut off, and the potential between the bridge connection points SV will be such that S is negative and ■ is positive. Therefore, the relay 13 operates with the voltage due to this potential difference,
By the operation of the relay, appropriate contacts are closed, and as in the above embodiment, fault detection devices such as a single alarm buzzer and an alarm lamp can be operated.

Although these obstacle detection tools are omitted in the drawings of the embodiments described below, they are provided in substantially the same way as in the embodiments described above.

When a short circuit fault occurs, the circulating current flowing through the transmission line increases, but the circulating current flowing through the rheostat R does not change, and contrary to the case of a disconnection fault, the circulating current flowing through the transmission line increases, and the current flowing through the bridge connection point SV increases.
Since the potential between S is positive and ■ is negative, the relay 14 operates, and by the operation of this relay, other alarm buzzers, alarm lamps, etc. can be operated.

FIG. 3 shows an example in which a differential voltage comparator is used as the response means.

In this device, a resistor Ra is provided on the sending end side of the transmission line, and a circulating current from the power source Ea is passed through the resistor.

- supplying the input terminal of the force differential type comparator 16 with the voltage occurring across the resistor Ra;

The voltage drop that occurs in the rheostat R in the circulating current path that circulates between the power source Es and the rheostat R is supplied as a reference voltage to the other input terminals, and this reference voltage is adjusted under normal conditions, so that there is no output to the comparator. Let's do it like this.

When a disconnection fault occurs, the voltage across the resistor Ra becomes zero, and the comparator outputs a positive voltage. This voltage makes the rectifying element 17 conductive, and the relay drive amplifier 19 operates, causing the relay 24 to turn on. Operate.

Furthermore, when a short circuit fault occurs, the voltage across the resistor Ra becomes higher than normal, and the comparator outputs a negative voltage, which causes the rectifying element 18 to conduct, causing the relay drive amplifier 20 to operate and the relay 22 to operate. Operate.

By operating these relays, fault detection devices such as alarm buzzers and alarm lamps can be operated.

Also, if a highly sensitive relay is used, the relay drive amplifier can be omitted.

In the above example, different relays are activated in the event of a disconnection fault and in the event of a short circuit fault, so for example, when a line fault occurs, a red alarm lamp and bell are activated, and in the event of a short circuit fault, an orange alarm is activated. It is also a good idea to make various changes such as having a lamp and buzzer working so that the type of failure can be easily identified.

If the DC resistance of the above-mentioned blocked wire is low, and a short circuit occurs near the end of the transmission line, the difference between the normal current flowing through the transmission line and the current flowing at the time of the short circuit may not be very large. In such a case, a resistor Rj may be connected in series with the blockage wire 1 to increase the difference and make it easier to detect the fault (FIG. 4).

Note that if the transmission line is branched into a plurality of branches from the middle, a blocking wire may be connected to the terminal end of each branch line.

Further, the interlocking switching means in each of the above embodiments may be a switch such as a rotary switch, or may be a suitable relay means.

Although a DC power source is shown as a power source for operating fault detection devices such as an alarm buzzer and an alarm lamp, it is of course possible to use an AC power source.

The present invention is configured as described above, and the status of the transmission line (actual transmission line) connecting the transmitter, receiver, etc. (normal, disconnection, short circuit)
In order to grasp this, a balanced network (
Since the pseudo transmission line (pseudo transmission line) is provided, the actual transmission line can be depicted on the normal pseudo transmission line, and when there is no normal transmission line, the pseudo transmission line and the actual transmission line are superimposed, so the response means will not operate and there will be no abnormality. If this occurs, this superposition is broken, and the response means that depicts this can operate accurately to detect an abnormality.

Further, since the above-mentioned balancing network includes a rheostat, when a fault occurs, when adjusting the rheostat to return the response means to an inoperative state, the resistance may be adjusted to increase or decrease. You can tell the difference between a disconnection and a short-circuit depending on the direction you adjust it.

Furthermore, receiving devices, such as cable broadcasting receiving devices, are generally scattered in various places, and there are several main circuits to connect them to the control center. For example, Chuo-dori (first branch line), Chuo-Higashi-dori (second branch line),
It is divided into branch lines such as Chuo Higashi Nidori Street (Third Branch Line).

In addition, within the premises of a company or factory, branch lines such as a new office line, first factory building, second factory, etc. are separated and connected to the main line.

In the case of a building, the first branch line is installed on the first floor, the second branch line is installed on the second floor, the third branch line is installed on the third floor, etc.

Even if the transmission line (actual transmission line) is branched into multiple parts in the middle, it is sufficient to connect an inductance element to the end of each transmission line, and the rheostat of the balanced network can be adjusted accordingly. By adjusting the number of branches, the same response means as in the case of one transmission line can be used regardless of the number of branches, and the number of transmission lines can be increased or decreased economically.

Furthermore, even when multiple branches are provided in the transmission line, when an abnormality occurs, it is possible to determine which branch line the failure occurred in by changing the rheostat in either direction (increase or decrease). You can know.

As described above, by installing the fault detection device of the present invention on the information transmission path, the administrator can be notified by an alarm as soon as a fault or abnormality occurs in the transmission path. By short-circuiting the transmission line to display the Morse code or other signals that were present, fault repair personnel can easily notify the management office that the restoration work has been completed from the fault site.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention. Figure 1 is a configuration diagram using a differential type relay, Figure 2 is a configuration diagram using a Wheatstone bridge, and Figure 3 is a configuration diagram using a differential type relay. Figure 4 is a partial explanatory diagram of the constituent countries when a comparator is used.

Claims (1)

[Scope of utility model registration request] It has two transmission lines to transmit information from an information source, a receiving device or telephone, etc. is connected between the transmission lines, and an inductance element having an impedance sufficient to block the information signal is connected at the end of the transmission line. On the other hand, a balanced network including a rheostat is provided to form a pseudo current circulation path equivalent to connecting an inductance element to the transmission path, and a DC current is passed through the transmission path and includes the transmission path in normal times. A direct current is passed through the current circulation path of the balanced network so as to cancel out the electrical or magnetic force generated in the current circulation path, and a direct current is applied to the current circulation path of the balanced network in response to the imbalance between the current circulation path including the transmission path and the current circulation path of the balanced network. Alternatively, if a response means that makes a mechanical change is provided, a failure detection device whose light emission or alarm is controlled in accordance with the response of the response means is provided, and a broadcasting device, telephone, or other information source is connected to the transmission path. A two-wire information transmission device having a failure detection device, characterized in that a filter is provided between the response means and the transmission path so that the energy of the information source does not flow into the response means.