JPS63972B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a power distribution line transport answer network used in a power distribution line transport system that transmits signals using power distribution lines and monitors and controls equipment such as switches on the power distribution lines. It relates to a signal transmitter.

Conventional configurations and their problems Today, in the power distribution sector, in order to provide electric power to general users with high reliability, the monitoring and control of power distribution equipment requires higher reliability as the number of devices to be monitored and controlled increases. For this reason, power distribution line transport systems using power distribution lines as signal transmission paths are beginning to be put into practical use. This signal transmission method can transmit signals to all locations where power can be supplied, making it an ideal transmission method for the power distribution sector, which has a large area. .

Figure 1 shows the basic configuration of the distribution line carrier answer backup system, where 1 is the main transformer of the substation.
It transforms to 77KV/6.6KV. 2 is
6.6KV wiring bus, 3, 4, and 5 are distribution lines branched from wiring bus 2, 6 is a current transformer for measuring the current of each distribution line, 7 is an answer back signal receiving device, and 8 is a 6.6KV/210V pole transformer, 9
is an answer backup signal transmitter, 450Hz±15Hz
The coded FSK current signal is injected into the distribution line, and approximately
Inject 20A signal. This 20A signal is sent to the 6.6KV distribution line via the pole transformer 8 with a current value of about 1/30 of 20A. The signal current flows toward the wiring bus 2 having the lowest signal impedance. The answer back receiving device 7 receives the current through the instrument current transformer 6. The above is the principle of answer backup.

FIG. 2 shows the basic configuration of a conventional answer back signal transmitter, and 10 is a pole transformer corresponding to 8 in FIG. Reference numeral 11 denotes an input switch such as a breaker for connecting the answerback signal transmitter to the pole transformer 10, which is installed inside the answerback signal transmitter. 12 is a DC power supply circuit that converts commercial frequency AC input into DC;
13 is an inverter circuit that generates a signal frequency of 450Hz±15Hz; 14 is an inverter circuit that efficiently passes the signal frequency to the pole transformer 10, and has a high impedance with respect to the commercial frequency so that the inverter circuit 13 is not affected by the commercial frequency. This is a coupling circuit designed as follows. 15 is a relay contact, which is open when not transmitting an answer back signal and closed only when transmitting a signal. The relay is then controlled by a control circuit 16. The control circuit 16 also has a function to control the inverter circuit 13.

The above is a general description of the answer back signal transmitter. By the way, the impedance of the pole transformer 10 to signals is very low (about 0.5Ω for a 10KVA transformer), and a large current flows with a small output voltage. That is, when the signal output current is 20A, the input current value at 60Hz is about 5A. Therefore, the current capacity of the input switch 11 is
Despite the 5A output current, a very large input switch must be used due to the 20A output current. Furthermore, as the current capacity increases, the dimensions also increase, resulting in an increase in the overall size of the transmitter.

OBJECTS OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to reduce the capacity of an input switch.

Structure of the Invention The present invention connects an input section to the low voltage side of a power step-down transformer via an input switch, and connects a signal output section via a relay contact that closes when a signal is transmitted. The rating depends only on the input current.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. Components that are the same as those in FIG. 2 are designated by the same numbers. As shown in the figure, the components are the same as those shown in FIG. 2, with the output relay contact 15 connected to the power supply side of the input switch 11.

By connecting in this way, the signal output current does not pass through the input switch 11, so the signal output current does not pass through the input switch 11.
The current value of 1 becomes very small. Further, the output relay contact 15 is a normally open contact and is closed only when a signal is transmitted. Therefore, when the input switch 11 is open, the DC power supply circuit 12 and the inverter circuit 1
3. No power is applied to the coupling circuit 15 and the control circuit 16. That is, the relay contacts 12 are open. Therefore, when the input switch 11 is opened, the entire circuit of the answer back signal transmitter is disconnected from the power supply.

Effects of the Invention As is clear from the above explanation, according to the present invention, the capacity of the input switch can be reduced by simply changing the connection of the output relay contact, thereby reducing costs and case dimensions. can.

[Brief explanation of the drawing]

FIG. 1 is a wiring diagram showing the basic configuration of the distribution line carrier answer back system, FIG. 2 is a block diagram of a conventional distribution line carrier answer back signal transmitter, and FIG. 3 is a distribution line carrier according to an embodiment of the present invention. FIG. 2 is a block diagram of an answerback signal transmitter. 10...Pole-mounted transformer, 11...Input switch,
12...DC power supply circuit, 13...Inverter circuit, 14...Coupling circuit, 15...Relay contact, 1
6...Control circuit.

Claims (1)

[Claims] 1 Distribution line carrying answer backup signal transmission by connecting the signal input section to the low voltage side of the pole transformer via an input switch and connecting the signal output section via a relay contact that closes only when the signal is sent. vessel.