FR2725083A1 - System switching apparatus e.g. for optical repeater in high voltage transmission line - Google Patents

Abstract

The apparatus includes a voltage feed unit (1A,1B) which is monitored by voltage (5) and current (7) comparators. Correct operation drives a logic state (8). A second logic state (B2) is generated from a detector which monitors the switching state. The logic states are monitored (15) in a further switch control logic circuit (16). An alarm (B4) monitors the correct operation of the logic. The control logic (B3) drives relays (181,182) which ensure correct connection of the power supply to the optical repeater (23).

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to an optical cable supply system for applying energy to an optical repeater for, for example, communication by submarine optical cable, and more particularly to an improvement to a system switching apparatus which performs a switching operation between the power supply unit of a current operating system and that of a backup system in accordance with the switching operation of an operator.

2. Description of the prior art
A conventional optical cable supply system -seuHnarIn comprises optical cable supply units for current and emergency operating systems having the same polarities. In order to switch these optical cable power supply units, the power supply units are activated so that the current and voltage applied to each of the two systems becomes equal between the two units and when they become equal, a lever external switching is activated.

 With the conventional system switching apparatus described above, however, since high voltage line operation is performed manually, the operator must touch the high voltage line. Therefore, a countermeasure must be taken for the protection of personnel. On the other hand, since a secondary accident can occur due to a malfunction, a countermeasure to prevent a malfunction is required. An operation to match the power conditions of the two units is inconvenient and time consuming. It follows that not only does the switching take time, but that an operating error can also be easily generated. Because the switching operation is performed manually, even a minor operating error can lead to disaster.

Summary of the invention
As described above, in the conventional system switching apparatus of the optical cable supply system, countermeasures for the protection of personnel and for the prevention of a malfunction must be taken against - high voltage line operation screws.

The operation required to match the power conditions of the two units after switching is inconvenient and takes time to satisfy the switching conditions. It follows that not only does the switching take time, but also that an operating error can be easily generated. Because the switching operation is performed manually, even a minor operating error can lead to disaster.

 The present invention has been developed in order to solve the problems mentioned above and its object is to provide a system switching apparatus for an optical cable supply system in which the control conditions are discriminated by means of circuits electric and in which high voltage lines can be precisely and safely switched in a short period of time without a manual operation but with the help of a simple automatic operation, and when the switching conditions are not met, an operation manual switching can be prevented by means of internal electrical circuits.

According to the present invention, there is provided a system switching apparatus which is used in an optical cable supply system comprising a current operation system supply unit and a backup system supply unit, and which realizes a switching connection of said current operating system supply unit and said emergency system supply unit to a supply device and to a test load having substantially the same characteristics as those of said supply device in accordance with a switching operation, said apparatus comprising:
system switching means comprising a first relay switch for selectively connecting an output terminal of said current operating system power supply unit to said power device and a second relay switch for selectively connecting an output terminal of said power supply backup system power supply unit to said power supply device, a third relay switch for selectively connecting said output terminal of said backup system power supply unit to said test load and a fourth relay -cIa switch for connecting selectively said output terminal of said power supply unit of current operating system to said test load ;;
voltage / current detection means for detecting output voltages and output currents from said current operating system power unit and said backup system power unit
an output condition discriminating means for obtaining a difference voltage and a difference current from the output voltages and output currents of said power supply units of current and standby operating system and for discriminating whether or not the difference voltage and the difference current respectively fall within permitted ranges;
switching operation detecting means for generating a switching control signal upon detection of a switching operation; and
switching control means which temporarily sets all of said relay switches of said system switching means in an activated state when said switching operation detecting means outputs a switching control signal while said discriminating means of the output condition determines that the difference voltage and the difference current fall within the authorized ranges so as to connect said power supply units of current and emergency operating system in parallel to each other and from this state, which establishes switches corresponding to some of said relay switches in a deactivated state so that said power unit of a desired system is connected to said power device and said power unit of the other system is connected to said test load.

 The switching operation detection means includes a mode selection function for switching between remote operation and local operation.

 The system switching apparatus includes state indicating means provided with light emitting elements corresponding to the relay switches of the system switching means. The light emitting elements are activated based on the switching control signal to thereby indicate the on / off states of the relay switches.

 The system switching apparatus includes alarm processing means for producing an alarm when the switching operation detecting means outputs a switching control signal while the output condition discriminating means determines that the difference voltage and the difference current do not fall within the permitted ranges.

 In the system switching apparatus of the optical cable supply system having the above-mentioned arrangement, following a switching between the supply units of the current operating system and the backup system, when the means for switching operation detection detects a switching operation while the output condition discriminating means determines that the difference voltage and difference current of the respective output voltages and currents fall within the allowed ranges, the control means of switching performs a control operation such that all relay switches are temporarily set to an activated state, hence the connection of the power supply units in parallel to each other. Relays of the system to be connected are established in a deactivated state. The state-to-off state switching operation is performed so that the potentials at the two terminals of each of the relay switches are equal, preventing electrical discharge at the contacts of the relay switches.

 The mode selection function of the switching operation detection means makes remote operation possible.

 The system switching means activates the light emitting elements based on the switching control signal so that the on / off states of the relay switches can be monitored.

 The alarm processing means generates an alarm when the switching operation detecting means outputs a switching control signal while the output condition discriminating means determines that at least either the difference voltage or the difference current does not fall within the permitted ranges. Thus, the operator can recognize an operating error.

 Additional objects and advantages of the invention will be highlighted in the course of the description which follows and will appear in part to be obvious in the light thereof or can be learned at the end of the implementation of the invention .

The objects and advantages of the invention can be achieved and obtained by means of instruments and combinations highlighted in particular below.

Brief description of the drawings
The accompanying drawings which are incorporated into and form part of the present description illustrate a presently particular embodiment of the invention and in association with the general description produced above and with the detailed description of the particular embodiment. produced below, they make it possible to explain the principles of the invention, and among these drawings:
Figure 1 is a block diagram which represents
The arrangement of the system switching apparatus of an optical cable supply system according to an embodiment of the present invention
Fig. 2 is a timing diagram which shows the timings of the system switching control operation of this embodiment; and
Figs. 3A to 3C show a connection of relay switches for explaining the switching control operation of the system switching block of this embodiment.

Detailed description of the particular embodiment
A particular embodiment of the present invention is described in detail with reference to the accompanying drawings.

 Figure 1 shows the arrangement of the system switching apparatus of a submarine optical cable supply system according to the present invention. With reference to FIG. 1, a voltage sensor 2A and a current sensor 3A as well as a voltage sensor 2B and a current sensor 3B are respectively connected to power supply units of system A (current operating system) and of system B (backup system) 1 A and 1 B. The voltage sensors 2A and 2B detect the voltage of the power outputs and the current sensors 3A and 3B detect the current of the power outputs. The outputs from the respective sensors 2A and 2B as well as 3A and 3B are applied to an output condition discrimination block B1.

 In the output condition discrimination block B1, the detection voltages of systems A and B detected respectively by the voltage sensors 2A and 2B are applied to a first difference voltage detector 4 and the difference voltage between the two voltages is detected by the difference voltage detector 4. This difference voltage is compared with a voltage value authorized by a voltage comparator circuit 5. The voltage comparator circuit 5 outputs a high level determination signal (H ) when the difference voltage is equal to or less than the authorized voltage value and a low level determination signal (L) otherwise.

 The detection currents of systems A and B detected respectively by the current sensors 3A and 3B are applied to a difference current detector 6 and the difference current between the two currents is detected by the difference current detector 6. This difference current is compared with a current value authorized by a current comparator circuit 7. The current comparator circuit 7 outputs a level determination signal H when the difference current is equal to or less than the value of authorized current and a level L determination signal otherwise.

 The determination signals output from the comparator circuits 5 and 7 are sent to an AND circuit 8.

The AND circuit 8 calculates an AND of the two inputs and outputs an H level condition determination signal (indicating that the switching conditions are satisfied) when the two determination signals are both H level and a determination signal L-level condition (indicating that the switching conditions are not satisfied) otherwise.

 A B2 switching operation detection block has remote and local modes. Mode switching is accomplished by activating a mode selector switch 9. More specifically, when the mode selector switch 9 is set to the level H side, a remote side door 10 is activated and a side door local 11 is disabled. When the mode selector switch 9 is set to the level side L, the remote side door 10 is disabled and the local side door 11 is enabled.

 A remote switch 12 is provided, for example on the operating panel of a central management system of submarine optical cable, and a cal switch 13 is provided, for example in the vicinity of the power supply units 1A and 1B . The two remote and local switches 12 and 13 are normally open (normally disabled) switches and output H-level switching operation signals while activated.

 The switching operation signals output from the respective switches 12 and 13 are selectively sent on an OR circuit (logical sum) 14 in accordance with the on / off state control operation of gates 10 and 11 respectively. OR circuit 14 outputs an H level switching command signal following the reception of a switching operation signal from one of the gates 10 and 11 and a level switching command signal L following reception of no switching operation signal from either of them.

 The condition determination signal output from the output condition discrimination block B1 and the switching control signal output from the switching operation detection block B2 are both sent to a control block B3 and an alarm processing block B4.

 In the switching control block B3, the condition determination signal and the switching control signal are input on an AND circuit 15. The AND circuit 15 calculates an AND of the two inputs and outputs a switching determination signal H level when the two signals are both H level and an L level switching determination signal otherwise. This switching determination signal is sent to a switching processing circuit 16.

 The switching processing circuit 16 detects the growth of the switching determination signal from level L to level H as a trigger and generates first and second switching control signals by means of a logic circuit, for example a flip-flop circuit. These switching control signals will be described later.

 The first and second switching control signals output from the switching control block B3 are both sent to a relay controller block 25 and to a status indication block B6.

 The controller block B5 has first through fourth relay controllers 171 through 174 for activating / deactivating first through fourth high voltage relay switches 181 through 184 of a system switching block B7.

 The first switch control signal sent from the switch control block B3 is applied to the first and third relay control devices 171 and 173 and the second switch control signal sent from the switch control block B3 is applied on the second and fourth relay control devices 172 and 174. The first and third relay control devices 171 and 173 establish the corresponding relay switches 171 and 173 in the activated state when the signals input to them are at a level L and in the deactivated state when the signals input to them are at level H. The second and fourth relay control devices 172 and 174 establish the corresponding relay switches 182 and 184 in the deactivated state when the signals which their inputs are of level L and in the activated state when the signals which have entered them are of level H.

 The status indication block B6 includes first to fourth light emitting diodes (LEDs) 201 to 204 corresponding to the first to fourth relay switches 181 to 184 and first to fourth LED drivers 191 to 194 for activating the LEDs 201 to 204.

The first switching control signal sent from the switching control block B3 is applied to the first and third relay control devices.
DEL 191 and 193, and the second switching control signal sent from the switching control block
B3 is applied to the second and fourth LED controllers 192 and 194. The first and third LED controllers 191 and 193 activate the corresponding LEDs 201 and 203 when the signals input to them are of level L and deactivate those -when the signals input to them are level H. The second and fourth LED controllers 192 and 194 activate the corresponding LEDs 202 and 204 when signals input to them are level H and deactivate them when the signals entered are of level L.

 In the system switching block B7, first and third relay switches of the normally closed (NC) type (normally in the activated state, called NC switches below) 181 and 183 are respectively connected between terminals a and t as well as between terminals c and P and second and fourth normally open (NO) relay switches (normally in the deactivated state, hereinafter referred to as NO switches) 182 and 184 are respectively connected between terminals b and c thus between terminals d and a.

This connection is generally called a trefoil connection.

 Terminal a is connected to the output terminal of system power supply unit A 1A, terminal c is connected to the output terminal of system power supply unit B 1B and terminal d is connected to an optical repeater 23 of an underwater optical fiber 22 by means of a supply device 21. The terminal d is connected to ground by means of a test load 24.

 The alarm processing block B4 comprises an operating error discrimination circuit 25, a horn control device 26 and a horn 27.

The operating error discrimination circuit 25 receives the condition determining signal from the output condition discriminating block B1 and the switching control signal from the switching operation detecting block B2 and determines a operation when the condition determining signal and the switching control signal are respectively of level L and of level H. The horn control device 26 activates the horn 27 when the operating error discrimination circuit 25 determines that an operating error has been made.

 The operation of the arrangement mentioned above is described with reference to Figures 2, 3A, 3B and 3C.

In the initial state, the switching processing circuit 16 of the switching control block B3 establishes both the first and second switching control signals at level L, as shown for a period
Ta of FIG. 2. At this time, the relay control devices 171 to 174 of the relay control device block B5 are all in the uncontrolled state and the switches NC 181 and 183 as well as the switches NO 182 and 184 of the system switching block B7 are respectively in the normally closed state and in the normally open state, as shown in Figure 3A. More specifically, the system supply unit A 1A is connected to the optical repeater 23 and the system supply unit B 1B is connected to the test load 24.

When the output difference voltage and the output difference current between the power supply units of systems A and B 1A and 1B are both within the permitted ranges, the output condition discrimination block B1 outputs a signal level condition determination
H.

 In this state, the remote / local mode is selected by activating the mode selector switch 9. When the switch 12 or 13 corresponding to the selected mode is activated, an activated level H operating signal is entered on the OR circuit 14 through gates 10 and 11 and the OR circuit 14 outputs an H level switching control signal.

 In the switching control block B3, since the condition determining signal is of level H, the switching control signal is sent to the switching processing circuit 16 via the AND circuit 15. When the switching processing 16 detects the transition of the switching control signal from level L to level H, it only modifies the first switching control signal to make it pass to level H, as shown in FIG. 2, and it activates the switches NO 182 and 184, as shown in Figure 3B. As a result, the power units of systems A and B 1A and 1B are respectively temporarily connected to the optical repeater 23 and to the test load 24 in parallel with each other.

 When a predetermined period Tb has elapsed, the switching processing circuit 16 passes the second switching control signal to the level H (a period Tc in FIG. 2) and deactivates the switches NC 181 and 183, as shown in Figure 3C. As a result, the system power unit A 1A is connected to the test load 24 while the system power unit B 1B is connected to the optical repeater 23.

From this state (the period Tc in FIG. 2), when the switch 12 or 13 is activated again and the circuit
OR 14 outputs a level H switching control signal, as the condition determination signal is at level H in the switching control block B3, this switching control signal signal is sent to the processing circuit switching 16 via the AND circuit 15.

 When the switching processing circuit 16 detects the transition of the switching control signal from level L to level H again, it restores only the second switching control signal at level L, as shown in Figure 2, and activates NC switches 181 and 183, as shown in Figure 3B. As a result, the power units of systems A and B 1A and 1B are respectively temporarily connected to the optical repeater 23 and to the test load 24 in parallel with each other.

 When another predetermined period Tb has elapsed, the switching processing circuit 16 restores the first switching control signal at level L (a period Ta in the right part of FIG. 2) and deactivates the switches NO 182 and 184, as shown in Figure 3A. As a result, the system supply unit A 1A is connected to the optical repeater 23 while the system supply unit B 1B is connected to the test load 24.

 More specifically, in the system switching apparatus of the optical cable supply system having the arrangement mentioned above, when a switching operation is to be performed between the supply units 1A and 1B, the fact of knowing if the voltages and currents output from the power supply units 1A and 1B are equal within the permitted ranges is detected. All the relay switches 181 to 184 are activated so that the power supply units 1A and 1B are connected in parallel to each other and then the switches of the system to be connected to the optical repeater 23 are deactivated. this arrangement and this operation, since the potentials of the two terminals of each of the relay switches 181 to 184 are equal, even if an on / off state switching operation is performed, an electrical discharge does not occur at the contacts and therefore, a failure problem and the like is not observed.

 In the status indication block B6, the LEDs 201 to 204 are activated by the first and second switching control signals, which indicates the activated / deactivated states of the corresponding relay switches 181 to 184. Thus, the states for connection of the power supply units of systems A and B 1A and 1B can be monitored.

 In the output condition discrimination block B1, when either the difference voltage or the difference current fall outside the permitted range, the condition determination signals take a level L. At this time, the signal switching determination of the switching control block B3 takes a level L regardless of the level of the switching control signal and the first and second switching control signals maintain the current level. Therefore, the system switching block B7 does not switch the system.

 In this state (in which the condition determination signal is at level L), when the remote or local switch 12 or 13 is activated and a level H switching command signal is output from the block. detection of switching operation B2, in the alarm processing block B4, the operating error discrimination circuit 25 determines that an operating error has been observed and activates the horn 27 via the horn control device 26. This informs the operator that the output states of the power supply units of systems A and B 1A and 1B do not coincide, which eliminates human error at the operator level .

 When the system switching apparatus having the above arrangement is used, high voltage line operation becomes unnecessary. Consequently, the operator does not accidentally touch a high voltage line. Personnel protection countermeasures become unnecessary and a secondary accident caused by a malfunction can be eliminated.

 Since the supply conditions of the respective supply units following a switching are automatically discriminated according to a timing produced by.

electrical circuits, the time required to satisfy the switching conditions can be shortened so that
The switching operation can be performed reliably in a short period of time. Manual operation is limited to the single switching operation. Even if an operating error should occur, the switching operation is prevented automatically. Therefore, a malfunction does not lead to disaster.

 When the switching conditions are not satisfied, not only an alarm sound is produced but in addition, a switch selection operation is prevented by means of an electrical control. Thus, human error can be prevented, which provides higher level security.

 The present invention is not limited to the embodiment described above but various variants and modifications can be made without departing from the spirit or the scope of the invention of course.

 As described above, according to the present invention, there is provided a system switching apparatus of an optical cable supply system in which the control conditions are discriminated by electrical circuits and high voltage lines. can be switched accurately and safely in a short period of time without a manual operation but using a simple automatic operation, and when the switching conditions are not satisfied, a manual switching operation can be prevented by the internal electrical circuits.

Additional advantages and modifications will be readily apparent to those skilled in the art. Therefore,
The invention in its broadest aspects is not limited to specific details or to the representative devices presented and described here. Consequently, various modifications can be made without departing from the spirit or the framework of the general inventive concept as defined by the present invention.

Claims (4)

 1. A system switching apparatus which is used in an optical cable power system comprising a current operating system power unit (1A) and a backup system power unit (1 B), and which makes a switching connection of said current operating system supply unit and said emergency system supply unit to a supply device (21) and to a test load (24) having substantially the same characteristics than those of said supply device (21) in accordance with a switching operation, said apparatus being characterized in that it comprises  system switching means (B7) comprising a first relay switch (181) for selectively connecting an output terminal of said supply unit :.  switch control means (B3, B5) which temporarily sets all of said relay switches (181-184) of said system switch means (B7) in an activated state when said switch operation detecting means (B2 ) outputs a switching control signal while said output condition discrimination means (bai) determines that. difference voltage and the difference current fall within the authorized ranges so as to connect said power supply units of current and emergency operating system (1A, 1B) in parallel with each other and from this state, which establishes switches corresponding to some of said relay switches (181-184) in a deactivated state so that said supply unit (1A, 1B) of a desired system is connected to said supply device (21) and that said power supply unit (1A, 1B) of the other system is connected to said test load (24).  switching operation detecting means (B2) for generating a switching control signal following the detection of a switching operation; and  output condition discriminating means (B1) for obtaining a difference voltage and a difference current from the output voltages and output currents of said power supply units of current and standby operating system (1A, 1 B) and to discriminate whether or not the difference voltage and the difference current fall respectively within authorized ranges  voltage / current detection means (2A, 2B, 3A, 3B) for detecting output voltages and output currents from said current operating system power supply unit (1A) and said power supply unit emergency system (lB) of a current operating system (1A) to said power supply device (21) and a second relay switch (182) for selectively connecting an output terminal of said backup system power supply unit (1B) to said power supply device (21), a third relay switch (183) for selectively connecting said output terminal of said standby power supply unit (1B) to said test load (24) and a fourth relay switch (184) for selectively connecting said output terminal of said current operating system power supply unit (1A) to said test load (24) ;;  2. Apparatus according to claim 1, characterized in that said switching operation detection means (B2) comprises a mode selection function (9) for switching between a remote operation and a local operation.  3. Apparatus according to claim 1, characterized in that it further comprises a state indication means (B6) provided with light emitting elements (201-204) corresponding to said relay switches (181-184) said system switching means (B7) for activating said light emitting elements (201-204) based on the switching control signal to indicate the on / off states of said relay switches (181184).  4. Apparatus according to claim 1, characterized in that it further comprises an alarm processing means (B4) for producing an alarm when said switching operation detection means (B2) outputs a signal of switching control while said output condition discriminating means (B1) determines that at least either the difference voltage or the difference current does not fall within the allowable ranges.