JPH0740682B2 - Transmission equipment - Google Patents

Description

Description: [Industrial field of use] The present invention relates to a transmission device for transmitting information using a distribution system.

[Conventional technology]

The development of power distribution systems is becoming more and more popular, as their utility as an information transmission medium is recognized while their utilization as electric power energy is becoming more sophisticated.

Power distribution systems are characterized by a wide variety of configurations and simple shapes, but with many branches.

In order to automate the operation of such a system, a so-called distribution automation method is being put to practical use, but in this, the method of using distribution line transportation has a configuration that is easy to deal with when the main circuit system is changed, It has been studied because it does not require an extra dedicated transmission line. However, in this method, there is a lack of certainty in its operation in the complicated configuration of the distribution line, and various principles have been devised.

Among them, the phase pulse signal method has been attracting attention as a load device control system, automatic meter reading and various information collecting system for low voltage distribution lines.

This conventional method is a method in which a commercial high frequency voltage of a distribution line is directly used to generate a transient high frequency vibration in an arbitrary phase and propagates it as a signal wave, the details of which are as follows.

In FIG. 1, (1) is a high voltage distribution line, (2) is a pole transformer, (3) is a low voltage distribution line, (4) is a transceiver (parent side),
(5) is a transceiver (child side).

In this method, a high-frequency resonant circuit is connected in the transmitter / receiver circuit at the power source end or the load end, and that circuit is turned on and off at a specified
By doing so, transient high frequency vibration of arbitrary phase is superimposed and generated on the commercial frequency power supply voltage waveform.

The principle diagram is shown in FIG.

In FIG. 2, (a) shows an equivalent circuit diagram of the phase pulse method, and (b) shows its waveform. The principle of this method is that the charge stored in the capacitor (51) at the load end (5) is discharged by the switch (53), and the impedance (1), (2), () is supplied to the load (6) or the power supply (0). The flow is divided through 3) and (20).

When the capacitor Co (51) is discharged at the load end, the current i ₂ flowing through the low voltage side of the pole transformer is detected on the way to the power supply end.

At this time, the waveform of the voltage emitted as a signal is, for example,
As shown in "Electrical Collaborative Research" Vol. 36, No. 5, P37-38, It is expressed as the reactance component of L = Z _H + Zt + Z _L.

In this method, the transmission frequency, phase, and level are affected by the transmission circuit constant, low-voltage distribution line, pole transformer, customer load, etc.

It is difficult to quantitatively grasp this variation, and it is considered that this method is one of the causes of the behavior that is considered to be relatively weak against noise.

[Object of the Invention]

The present invention solves the above-mentioned drawbacks of the conventional device and provides a new method.

Example of Invention

The principle of the present invention is shown in the equivalent circuit diagram of FIG. In FIG. 3 (a), (0) is a commercial frequency power source, (1) is a high-voltage side impedance, (2) is an equivalent impedance of a transformer, (3) is a low-voltage side impedance, and (4) is Master side receiver (sender), (40) CT for signal reception, (5) slave side (receiver) transmitter, (51) capacitor for transmission circuit, (52)
Is a reactor, (53) is a transmission switch, and (6) is a load. The above (1) to (6) are essentially the same as the equivalent circuit diagram of the phase pulse system of FIG. 2 (a).

In the present invention, a transformer (50) is added to the slave side transmission (reception) receiver (5).

The transformer (50) measures the shunt flow to the load (6) caused by discharging the electric charge of the capacitor (51). The measurement result is added to the transmitter (receiver) transmitter (5) and The feature is that the transmission signal to the side is added to the information of the own-end load transmitted from the own end.

As a result, by accurately adding the amount that has diverted to the load side, the loss to the load side at the time of transmission can be added to the information signal on the slave side, and if there is a change in the line propagation state, a signal that considers the presence or absence of that change. It becomes possible to send.

Next, FIG. 3 (b) shows the principle of the present invention including the connection on the pole transformer side.

In FIG. 3 (b), (0), (2) and (6) are the same as those in FIGS. 2 (a) and 3 (a). (twenty one),
(22) is a CT connected to the high voltage side and the low voltage side, and the connection is differential. This output is introduced into the power receiving (transmitting) transmitter (4).

The transmission signal from the load side is applied to the receiving (transmitting) transmitter (4) via the signal receiving CT (40), but the pole transformer is a nonlinear impedance with saturation characteristics, so the capacitor on the high voltage side is It shows complicated behavior due to the transient phenomenon caused by opening and closing of etc.
Therefore, the differential current (algebraic sum) flowing in the shunt indicating the excitation in this equivalent circuit is detected, and this signal-receiving CT (including 40 ₀ , 60 ₀ , 80 10 ₀ ) contains a specific frequency component (for example, 4 ₀ , 60, 8 ₀ 10 ₀ ). 40)
The decision to partially cancel or change the reception determination of the reception signal of the reception (transmission) transmitter (4) obtained via the above is taken into consideration.

In particular, the transient phenomenon that occurs when the power factor correction capacitor connected to the high voltage side is turned on is caused by resonance with the short-circuit current suppressing reactor connected in series, although the waveforms are different, and the generation mechanism itself is the same. When entering the low voltage side from the high voltage side through the pole transformer, it is easy to saturate the above transformer operating at a high magnetic flux density level with direct current depending on the phase, and therefore take even harmonics. It will be. By directly detecting such a phenomenon in the vicinity of the receiving end, an abnormal state can be monitored, and when a transmission failure occurs, it is possible to give certainty by discriminating the received waveform.

In addition, when there is an instantaneous change in the voltage on the high-voltage side of the transformer, such as switching on the high-voltage side, the harmonics caused by transient phenomena caused by the shunt current flow to the excitation impedance shunt caused by the non-linear excitation characteristics of the pole transformer as well. Similarly, when the received waveform is disturbed by the waveform and the transmission failure occurs, the certainty can be given by discriminating the received waveform.

In short, in this method, the side path generated at the transmission (reception) end is detected on both sides of the power supply / load, and the abnormalities caused by the nonlinearity of the pole transformer close to the reception side. It is possible to detect a phenomenon and correct the discrimination logic on the receiving side by using the detected phenomenon, thereby further improving the certainty of signal transmission and reception.

The basic configuration of one embodiment of the present invention is shown in FIG. In FIG. 4, (1) to (5) are (1) to (5) in FIG.
And its function is almost the same. In this embodiment, CT (21a) and (21b) are on the high pressure side, and CT (22a) and (22 are on the low pressure side.
b), on the low voltage side, close to the PT (31a), (31b) parent side receiving (transmitting) receiver (4), and CT (40a), (40b), child side transmitting (receiver) receiver (51) CT (50a) and (50b) are installed in close proximity, and
The second difference is that measurement / processing function circuits (41) and (54) are added.

The CT (50a) (50b) and the measurement / processing function circuit (55) are for realizing the above-mentioned principle FIG. 3 (a).
(21a) (21b), CT (22a) (22b), PT (31a) (31b) and measurement / processing function circuit (41) are based on the above-mentioned principle FIG. 3 (b).
Is to realize.

Next, the detailed configuration and operation of the circuit will be described below. FIG. 5 shows the configuration of the slave station side (transmission end) of an embodiment of the present invention.

In Fig. 5, (5), (50-a), (51), (52),
(53) is the same as that of FIGS. 3 and 4. (55a)
Is a level converter that converts the instantaneous value waveform on the secondary side of CT (50-a) to an appropriate level. Reference numeral (56a) is also a level converter for converting the low voltage circuit voltage into one having an appropriate level of the instantaneous value waveform. (57
a) and (57b) are sample and hold amplifiers that store the output waveform of the level converter. Reference numerals (58a) and (58b) are control circuits for controlling the sample and hold. The sample and hold amplifiers (57a) and (57b) detect the appropriate phase (for example, 0) of the system voltage and sample the current waveform at this time. Generate a sample pulse. As a result, the transmission current synchronized with the power supply frequency can be detected.

(59) is a multiplexer, which switches the sample hold value of the sample hold amplifiers (57a) (57b) and applies it as an input to the A / D converter (60) in the next stage.

In the above A / D converter (60), multiplexer (59)
The output analog voltage of is input and converted into a digital value and applied to the subsequent microprocessor (61).

Although not described, the three-phase circuit has a similar circuit configuration between the b-phase and the n-phase, the input is taken from the system side, added to the sample hold amplifier (57b), and controlled by the control circuit (58b). Take it into the A / D converter (60).

In this circuit, the input side of the level converter (56a) may use PT if necessary. Although the functions of the level converter and the PT are essentially the same, the PT is not used for the sake of simplicity.

Next, the operation of the slave station side according to the embodiment of the present invention will be described.

First, when transmitting data from the slave station side to the master station side, the slave station side receives the measured value from the solid state meter (7) in response to the data transmission request, and then transmits to the slave side transmission (reception) receiver (5). The transmission control circuit (TCC) creates a pulse train and applies it to the thyristor gate control circuit (GCC) at the next stage. The thyristor module (3) fires upon receiving the output pulse of the gate control circuit GCC, and a free vibration pulse waveform is sent to the external circuit from the capacitor (51) and the reactor (52) according to the number of times of firing.

Here, since the high-frequency pulse signal has a smaller impedance on the power source side than the impedance on the load side, most of it flows to the power source side, but a load such as a capacitor having a low impedance with respect to high frequencies is connected to the load side. Then, the pulse is shunted to the load side from the capacitor (51).
Since a current also flows on the primary side of the CT (50-a), a current also flows on the secondary side of the CT (50-a) and is held in the sample hold amplifier (57a) by the level converter (55a). However, at this time, since the low-voltage line voltage is level-converted and added to the control circuit (58a), the polarity and the interval are set according to the command from the microprocessor (61) and the voltage applied to the capacitor (51) is changed. If the discharge timing and the voltage across the capacitor (51) are held in the same direction as the polarity, the current waveform synchronized with the sign of the line voltage can be sampled and held.

That is, the load outflow amount of the phase pulse when the transmission switch (3) is closed can be measured.

Next, the analog value thus obtained is switched by the multiplexer (59), becomes a digital value by the A / D converter (60), is fetched by the microprocessor (61), and is stored in the memory.

The size, frequency, and phase of the outflow current waveform stored by this microprocessor (61) are analyzed at high speed by the microprocessor (61), and the values are used for the signal transmission of the slave side transmission (reception) receiver (5). Is applied to the transmission control circuit TCC, and the above information is superimposed on the information to be transmitted in the next transmission cycle and transmitted. Upon receiving the information on the outflow current, the master side receiving (transmitting) transmitter (4) judges whether to adopt the previously received information or to make another transmission request based on the information. To do.

Since the load condition in the distribution line does not change within 10 cycles of the commercial frequency, even if the above-mentioned outflow is detected and applied to the next or the closest cycle, practically no great difference occurs.

Further, when the transmission control circuit has a proper intelligence, it is possible to change the operation of this control circuit to change the level of the transmission pulse.

FIG. 6 shows the configuration of the master station (reception end) of an embodiment of the present invention.

In FIG. 6, (1), (2), (3), (4), (40
a) (40b), (40n), (21a), (21b), (21n) have the same names and functions as those in FIG.

(41) is a measurement processing circuit, which includes the following components. That is, (42a) and (42b) are three-layer current transformers (CT),
(43a) and (43b) are level converters that receive the outputs of the current transformers (42a) and (42b) and perform level conversion. Further, (44a) and (44b) are level converters (43
The sample-hold amplifier (45) receives the outputs of (a) and (43b) and is controlled by the phase lock loop, which will be described later, to hold and reset the sample-hold amplifier (44).
a) and (44b) are applied to the A / D converter (46) in the subsequent stage by switching the outputs, and (46) is a sample-hold amplifier (44a), (a) added via the multiplexer (45). 44b) A to A / D conversion of analog output
It is a / D converter.

(47) is a microprocessor which reads the digital value of the output of the A / D converter (46) and performs measurement calculation processing, and has an appropriate speed and memory capacity.

(48) is a level converter that receives the line voltage (3) of the low-voltage system and converts it into a voltage of appropriate magnitude, and (49) is a control circuit that controls the sample-hold amplifiers (44a) and (44b). 49), (44a) and (44b) are on the slave station side (58a)
Since the functions of (58b), (44a) and (44b) are almost the same, detailed description thereof will be omitted, but outputs from the voltage 0 to the next 0 are applied to the sample and hold amplifier in synchronization with the voltage of the system, and the same phase as the voltage is applied. Holds the current input of and enables reading.

As is clear in the figure, CT (42a) receives the secondary current of CT (40a) and uses the received current of the master station as input.

CT (42b) is the current of CT (40a) (40b) and CT (21a) (21
b) The combined current (that is, the differential current) of (21n) is received, and the presence or absence of current flowing into the high and low voltage interconnection circuit portion including the transformer (2) is detected.

Next, the operation of the master station side measurement processing circuit will be described.

The current that superimposes the phase pulse transmitted from the slave station side as described above is detected by CT (40a) (40b) (40n) and is sent via CT (42a) (42b) to the level converter (43
a) Level conversion (for 3 phases), held by sample hold amplifier (44a), passed through multiplexer (45) and converted to digital value by A / D converter (46) and read by microprocessor (47). Get caught At this time, the output of the control circuit (49) is synchronized with the system voltage change and some values within a predetermined duration are read as sample values.

This value is read in several times and compared with the characteristics of the waveform of the oscillation signal of the immediately preceding pulse train transmitted from the transmission end, and if they match, the correct pulse is received.

With this pulse train consisting of a plurality of correct pulses, the measurement data on the child side, the data indicating the shunt state of the pulse on the transmission side, and the data showing the characteristics of the waveform are decoded and checked as measurement values to make them official data.

That is, the characteristic of the vibration waveform of the phase pulse is detected in an analog manner, and the characteristic of the same waveform detected on the transmitting side is compared with a value verified by the received data to perform an analog test. The pulse signal train sent out as described above appears instantly at the receiving end and is observed as a waveform in which a phase pulse is superimposed on the commercial frequency.Therefore, on the receiving side, the pulse train corresponding to the desired measurement data and the above-mentioned The pulse train corresponding to the current flowing out and leaking to the load side will be received. Since the latter pulse train will be sent in addition to other measurement data observed at the same transmitting end, if the logic for discriminating the received code is set appropriately, what is the state of transmission of the transmitted signal? Moreover, it is possible to determine whether or not there is a change.

Also, by analog demodulating the analog peak value of the received pulse and the pulse train for which the result of measuring the analog value of the outflow pulse is added, the state of the waveform of the phase pulse on the transmission side is faithfully reproduced in an analog manner. Things are possible.

Further, pulse-shaped currents that pass through this transmitter and receiver may occur from the high-voltage side or low-voltage side, but since these are observed as the same waveform at the transmission end and the reception end, the reception end The influence can be removed by canceling out the signal during the reproduction process. That is, at the transmitting end,
Since the pulsed current that becomes noise can be detected together with the transmission signal, the noise information can be transmitted in the next transmission cycle.
At the receiving end, the noise information is removed from the previously received data based on this noise information. At this time, since the transmitting end and the receiving end observe the same waveform, faithful reproduction can be performed.

The waveform applied to the level converter circuit (three phases) (43b) is an algebraic sum of the currents flowing into and out of the pole transformer (2), and therefore is always relatively small. As described in the principle, when the excitation state of this transformer (2) changes rapidly, the exciting current flows largely and the algebraic sum of the inflow and outflow currents is larger than a certain value, and CT (42b) The input added will be large.

Especially when there is a sudden change in the voltage of the system, it is not necessary to send and receive the phase pulse signal, so it is desirable to detect the situation at this time and invalidate the sent and received signals.
(42b) has an input and this is a level converter (43
b), via the sample-hold amplifier (44b), after switching by the multiplexer (45), the A / D converter (46)
Read processing by.

Generally, the harmonic components generated by the DC saturation of the transformer due to the sudden change in the voltage applied to the transformer include many even-order harmonic components with respect to the fundamental frequency, so the harmonic components at this time are analyzed by the microprocessor (46). A program based on an algorithm stored in advance is incorporated to make a determination.

The detection of the phase pulse signal on the low-voltage system side, which is usually detected by CT (40a) (40b), is higher than the system frequency and sufficiently higher than the harmonics generated by the saturation of the transformer that occurs when the system is opened and closed.

Therefore, if the operating cycle of the A / D converter (46) or microprocessor (47) that has a speed that can detect the phase pulse in an analog manner with appropriate accuracy is selected, the transient harmonic components generated by the above-mentioned system switching The operation cycle necessary for detecting the signal is sufficiently long and can be sufficiently realized without increasing the burden on the operation cycle of the microprocessor (47).

In addition, the power factor correction capacitor installed on the high voltage side produces a fourth harmonic that resonates with the built-in series reactor, which penetrates into the pole transformer and causes DC saturation, resulting in a new higher harmonic on the low voltage system side. There is a possibility, but it can be discriminated and separated from the low-voltage side phase pulse signal by detecting it in an analog manner by the above-mentioned differential voltage detection circuit and making a digital wave by the microprocessor (47). .

〔The invention's effect〕

As described above, according to the present invention, it is possible to prevent transmission errors due to leakage signals flowing out to the load side and reduce transmission errors. This has an effect of preventing an erroneous determination by detecting a portion due to a change in the operating state.

Although the present invention has been described above with reference to one embodiment, the present invention is not limited to this embodiment, and several other modifications are possible. It goes without saying that these are included in the scope of the present invention without departing from the spirit of the present invention.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a basic configuration of a conventional device, FIG. 2 shows a principle of a phase pulse system, (a) is an equivalent circuit diagram,
FIG. 3B is an explanatory waveform diagram, FIGS. 3A and 3B are equivalent circuit diagrams showing the principle of the present invention, and FIG. 4 is a configuration diagram showing one embodiment of the present invention, FIG. FIG. 6 is a detailed configuration diagram of a part thereof. (0) …… Commercial frequency power source, (4) …… Parent side receiving (sending) receiver, (5) …… Slave side sending (receiving) receiver, (40) (40a) (40
b) (40c) …… CT for signal reception, (50) (50a) (50b)…
… Transformers, (51)… Transmitting circuit capacitors, (52)…
… Reactor, (53) …… Switch for transmission, (6) …… Load, (55a) (56a) …… Level converter, (57a) (5
7b) …… Sample-hold amplifier, (58a) (58b) ……
Control circuit, (59) …… Multiplexer, (60) …… A / D
Converter, (43a) (43b) …… Level converter,
(44a) (44b) …… Sample-hold amplifier, (46)…
… A / D converter, (45) …… Multiplexer, (47)
…… Microprocessor, (48) …… Level converter, (49) …… Control circuit. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] 1. A transmission device for injecting a high-frequency signal into the distribution system in synchronization with the voltage of the distribution system to transmit and receive the high-frequency signal. The transmitter / receiver that transmits the signal, the detector that detects the outflow current that flows out to the load side in the high-frequency signal that is transmitted from this child transceiver, and the information on the outflow current that this detector detects is close to The transmission device comprising means for superimposing on the high frequency signal and transmitting the superposed signal to the master side transceiver in the transmission cycle. 2. A transmission device in which a high-frequency signal is injected into the distribution system in synchronization with the voltage of the distribution system to transmit and receive the high-frequency signal, in the vicinity of a pole transformer that interconnects the high-voltage and low-voltage systems. A transmitter / receiver installed to transmit / receive the high-frequency signal, a detector for detecting current flowing in / out of the pole transformer, and controls the reception result received by the transmitter / receiver based on the inflow / outflow current detected by the detector. A transmission device comprising: