JPH098711A - Ground return carrier system - Google Patents

Abstract

PURPOSE: To exactly communicate information, which is exchanged between a transmission part and a reception part, between a grounding phase and ground. CONSTITUTION: At a transmitter 7, plural pieces of information are outputted by an input I/F part 41 corresponding to the input request of a CPU 42, and this information is arranged at an information position on a timing signal corresponding to an input number by the CPU 43. Then, a transmissive signal is generated by superimposing a carrier on this timing signal at a modulation part 45 and injected to a ground line 3 by a signal injector 5 after power is amplified by a power amplifier part 49. At a receiver, a received signal is inputted from the gap between the grounding phase and the ground by a signal reception input part, the signal dispatched to the input part and attenuated is amplified, and a signal on an unwanted band or a noise component is removed by a band pass filter. Then, the timing signal is demodulated from the received signal by a demodulation part, and arbitrary data are reproduced from the prescribed part of the timing signal by a CPU and outputted from an output I/F part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground return transportation system, and more particularly to a ground return transportation system capable of accurately communicating information transmitted / received between a transmitter and a receiver via a ground phase and the ground. .

[0002]

2. Description of the Related Art Generally, in a private power receiving facility, as shown in FIG.
The low piezoelectric path 105 is arranged via the
Power is supplied to the load device via. For the low piezoelectric path 105, a zero-phase current transformer such as a detection zero-phase current transformer 109 is arranged via a second-class grounding grounding wire 107,
When insulation deterioration or the like occurs in the low piezoelectric path, the zero-phase current transformer 10
The detector 113 connected to 9 is used for detection. Then, the detection signal of the insulation state detected by the detector 113 is supplied to the low piezoelectric path 10 by using the signal injection input unit 111.
The signal from the detector 113 can be received at an arbitrary position on the low piezoelectric path by using the alarm 117 transmitted to the low piezoelectric path 105. Further, the notification device 117 is provided with means for outputting a signal to the monitoring center via a telephone line or the like, and constantly monitors the status of insulation deterioration or the like in many private power receiving facilities at a monitoring center arranged in a remote place. I am able to do so.

As described above, when the detector 113 detects insulation deterioration or the like in the low piezoelectric path and the notification device 117 uses the low piezoelectric path 105 as a transmission path to receive a signal, the detector 113 is used. The signal output from the injection input unit 111 induces a continuous AC signal so as not to match the commercial power supply frequency and its harmonic frequency. The signal sent from the injection input unit 111 uses an AC signal of a different frequency for each type of insulation alarm detected by the detector 113. For example, 1477 Hz for normal operation and 1336 H for caution.
z, and 1209 Hz in the case of caution. In addition, when setting a specific frequency as described above in association with each signal type, other frequencies are used in association with each signal, and the notification device 117 uses the transmission signal from the detector 113. It receives and demodulates and notifies using an alarm sound or displays using an alarm indicator light. further,
It has a function of automatically outputting an alarm signal from the terminal 119 of the data transmission circuit to a monitoring center or the like through a telephone line from the signal received by the alarm device, if necessary.

In the device shown in FIG. 7, the detector 1
The AC voltage induced by the injection input unit 111 on the second-class grounding work ground wire by 13 is transmitted by the low-voltage path and detected by the alarm 117 as a ground AC voltage. Further, inside the alarm device 117, a number of bandpass filters corresponding to the type of alarm are arranged (three when transmitting three kinds of information), and each frequency induced by the detector 113 is centered. The level of the component is detected, and when the value exceeds a certain level, it is determined that the corresponding alarm signal is received. Therefore, in the notification device 117, it is necessary to provide a bandpass filter so as to allocate individual frequencies according to the number of information to be transmitted, and therefore, the signal processing circuit of the notification device 117 has, for example, three types of frequencies. In the case of using the above signal, three sets of signal processing circuits are arranged respectively.

[0005]

However, since office equipment incorporating semiconductors is often used in power receiving equipment for private use, noise is output from the office equipment toward the low-voltage path and insulation monitoring is performed. Noise near the frequency of the alarm used in the device and noise within the transmission band tend to increase.

Further, in the insulation monitoring device, since the band pass filter in which the frequency is assigned to each alarm is used, the reception frequency band is widened in the notification device 117, and the detector is caused by the noise component in the reception frequency band. Even though 113 outputs the frequency in the insulation normal state, the alarm 117 adds the noise frequency component to the frequency component in the insulation normal state and converts it into the frequency component in the insulation abnormal state. As a result, there may be a case where it is determined that an insulation abnormality has been received, and there is a problem that a false alarm is output.

Further, there is a problem that a carrier wave cannot be normally received, that is, a so-called carrier wave abnormality occurs due to the influence of noise components in and around the pass band of the notification device.

In addition to the above-mentioned problems, when a method of allocating a frequency to each information to be transmitted is used as in the conventional insulation monitoring apparatus, if an attempt is made to increase the number of types of information to be transmitted, further reception is required. It is necessary to widen the frequency band.

Further, when there are a plurality of reception frequencies in the notification device 117 arranged for reception, it is necessary to arrange as many bandpass filters as there are reception frequencies.
Since the output of the receiving unit 17 is the sum of a plurality of band pass filters, the receiving frequency characteristic of the receiving unit widens the receiving frequency band as the number of receiving frequencies increases, and becomes weak against noise. However, there was a problem that it became easier to receive interference.

When the reception frequency band is widened, a false alarm,
Since there is a possibility that carrier wave anomalies will occur frequently, it has become difficult to configure means for transmitting various types of information. Therefore, in the insulation monitoring device as described above, even if a device is configured to transmit other information in addition to the three types of signals such as normal, caution, and warning, using another frequency, There is a problem that the carrier wave is likely to be unable to be normally received due to the frequency of noise flowing in the electric path 105.

[0011] The present invention has been made in view of the above,
It is therefore an object of the present invention to provide a ground return transportation system capable of accurately communicating information transmitted and received between a transmitter and a receiver between a ground phase and the ground.

[0012]

According to the first aspect of the present invention,
In order to solve the above-mentioned problem, while the information from the information source is electromagnetically injected into the second-class grounding grounding wire of the low-piezoelectric path by the transmitting unit and is conveyed, the information conveyed to another position on the low-piezoelectric path. In the earth return transport method of receiving from between the ground phase and the ground in the receiving unit, in the transmitting unit, the input information from the plurality of information sources is arranged at the information position on the timing signal according to the input number, A transmission signal is generated by modulating a carrier based on the presence or absence of information on the timing signal, and the transmission signal is electromagnetically injected into the second-class grounding construction ground line, while the receiving unit separates the different position. The gist is to input a received signal from between the ground phase and the ground, demodulate a timing signal from the received signal, and then reproduce each information from a predetermined information position of the timing signal.

In order to solve the above-mentioned problems, the invention of claim 2 reproduces the information by sampling a plurality of times every a predetermined time has elapsed from the header end position or header start position included in the demodulated timing signal. However, the main point is to reproduce the data based on the majority result of the presence or absence of the data.

According to a third aspect of the present invention, in order to solve the above problems, the reproduction of the information reproduces a plurality of pieces of information from the demodulated timing signal, and at least two pieces of the plurality of pieces of reproduced information are at least one. If so, the point is to decide that it has been reproduced normally.

[0015]

According to the first aspect of the invention, in the transmitting section, the input information from the plurality of information sources is arranged at the information position on the timing signal according to the input number, and the carrier is provided with or without the information on the timing signal. Generate a transmission signal that is modulated based on, and electromagnetically inject the transmission signal into the ground wire of the second type grounding work, while at the receiving unit, receive the reception signal from between the ground phase at another position and the ground. , After demodulating the timing signal from the reception signal, by reproducing the respective information from the predetermined information position of the timing signal, the information transmitted and received between the transmission unit and the reception unit can be transmitted between the ground phase and the ground. I try to communicate accurately.

According to the second aspect of the invention, the information reproduction is
Information transmitted from the transmitter by sampling multiple times each time a predetermined time has elapsed from the header end position or header start position included in the demodulated timing signal and reproducing the data based on the majority result of the presence or absence of data. Is accurately received between the ground phase and the ground.

According to the third aspect of the invention, the information is reproduced as
A plurality of pieces of information are reproduced from the demodulated timing signal, and when the plurality of pieces of reproduced information match at least two or more pieces, it is determined that the pieces of information transmitted normally are reproduced, and thus the information transmitted from the transmitter is transmitted. I am trying to receive correctly between the ground phase and the ground.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a system configuration of a ground return transportation system according to an embodiment of the present invention. In FIG. 1, the three-phase transformer 1 is supplied with 6600V on the high-voltage road side, while it is grounded to the ground via the second-class grounding grounding wire 3 on the low-voltage road side and used as a power receiving equipment for private use. Three-phase power transmission is performed.

The information output device 7 is a device for outputting arbitrary information. For example, like the insulation monitoring device, it outputs the insulation monitoring result monitored by the ground line 3 as normal information, caution information and warning information. is there. The transmitter 9 is a second-class grounding grounding wire 3 that is grounded between the low-voltage path 2 and the ground 15.
The information from the information output device 7 is electromagnetically injected into the device via the signal injection transformer 5.

On the other hand, the receiver 13 receives the information from another position on the low piezoelectric path 2 between the ground phase and the ground.

FIG. 2 is a diagram showing the structure of the insulation monitoring device 19 which plays the role of an information source. In the figure, the second-class grounding work grounding wire 3 connected to the low piezoelectric road side of the three-phase transformer 1.
An insulation monitoring voltage injector 21 and a leakage current detection transformer 23 are connected to (hereinafter, simply referred to as “ground wire”).

Next, FIG. 3 is a diagram showing the structure of the transmitter 7. In the figure, inputs 1 to 5 are a plurality of arbitrary information. For example, input 1 includes normal information, caution information, and warning information output from the output terminal 39 of the insulation monitoring device 19 as shown in FIG. Is entered.

The input I / F unit 41 inputs 1-bit information generated by a plurality of information output devices to the inputs 1 to 5, respectively, and latches the input information to CP.
In response to an input request from U43, 5 bits are collectively output to the CPU 43. The CPU 43 has a control program and control data for controlling the entire transmitter 7,
The timing signal corresponding to the 5-bit information input in response to the input request is generated.

The modulator 45 oscillates the oscillation frequency F of the crystal oscillator 47 as a fundamental frequency, divides the frequency F into a carrier carrier frequency of about 1 KHz by a predetermined division ratio, and then outputs from the CPU 43. A carrier signal is superimposed on a timing signal having a plurality of pieces of information to generate a transmission signal.

The power amplification section 49 is a power amplifier that amplifies the power of the transmission signal output from the modulation section 45.

The signal injector 5 is a current transformer having an output impedance of about 1Ω with respect to the commercial frequency on the ground line 3 on the secondary side.

Here, the transmission signal power-amplified by the power amplification unit 49 reaches the signal reception input unit 11 of the receiver from the ground line 3 via the low piezoelectric path 2, and a part of the transmission signal is received here. Signal from the signal receiving input unit 11 to the ground at the point C of the earth 15 and then to the ground line 3 that is grounded at the point E via the return path D of the earth 15 Return to the injection transformer 5.

Next, FIG. 4 is a diagram showing a timing signal having information output by the CPU 43 of the transmitter 7. FIG. 4A shows a timing signal of n-bit data sandwiched between two headers (A).
Here, the time tA during which the header (A) stands is set to 2 seconds. Further, there is provided a time t1 = 0.5 second in which the carrier is not superposed after the header (A) falls. Furthermore, the first bit of data corresponding to input 1 has ta = 1 at the information position t1 after the falling edge of the header (A).
Stand up for a second.

In response to such a basic timing signal, for example, when data "1" is transmitted to the information position of the second bit corresponding to the input 2, t2 = 2 seconds after the header (A) falls. After that, ta = 1 second rises. On the other hand, 2
When the data "0" is sent to the bit, the data "0" remains as it is for 1 second after t2 = 2 seconds after the header (A) falls.

Therefore, it is possible to set arbitrary data corresponding to the input n in the n-bit data sandwiched by the two headers (A).

In FIG. 4B, for example, the input I / F
Since the inputs 1 to 5 are input to the unit 41, the number of bits sandwiched between the two headers (A) is 5 bits. Further, since "1" is set to transmit the carrier of only the third bit, it can be shown that only the input 3 has an input. That is, the presence or absence of an input signal can be indicated.

Next, the operation of the transmitter 7 used in the earth return transportation system will be described. In the transmitter 7 that transmits information,
The input I / F unit 41 inputs the respective 1-bit information generated by the plurality of information output devices to the inputs 1 to 5, respectively,
Each input information is latched into a 5-bit unit data, the 5-bit data is output to the CPU 43 according to the input request of the CPU 43, and then the 5-bit data input by the CPU 43 according to the input request is input. It is arranged at the information position on the timing signal according to the number. Next, the modulator 45 oscillates the oscillation frequency F of the crystal oscillator 47 as a fundamental frequency, divides this frequency F into a carrier carrier frequency of about 1 KHz by a predetermined division ratio, and then C
The carrier signal is superimposed on the timing signal having the information output from the PU 43 to generate a transmission signal. Next, the power amplification unit 49 performs power amplification on the transmission signal output from the modulation unit 45, and the power amplified transmission signal is output to the signal injector 5.
Since it is injected into the grounding wire 3 on the secondary side, the information transmitted from the transmitter can be accurately transmitted through the grounding work grounding wire of the second kind.

Next, FIG. 5 is a diagram showing the configuration of the receiver 13. In the figure, the signal reception input unit 11 receives a transmission signal from the transmitter 7 carried on the second-class grounding grounding line 10 from between the ground phase and the ground, and inputs it to the input unit 51 as a reception signal. It is something to hand over.

The input section 51 is an amplifier for amplifying the transmission signal attenuated by the low piezoelectric path 2. The bandpass filter 53 is a filter that attenuates a signal having a frequency component distant from the center frequency while removing a noise component, while allowing the carrier carrier frequency around 1 KHz to pass therethrough. The demodulation unit 55 outputs 1 KH from the received signal.
The carrier signals before and after z are deleted and the timing signal is demodulated. The CPU 57 has a control program and control data for controlling the entire receiver 13, and reproduces arbitrary data transmitted from the demodulated timing signal.
The output I / F unit 59 outputs the data reproduced by the CPU 57 to any one of the outputs 1 to 5.

Next, the operation of the receiver 13 used in the earth return transportation system will be described. In the receiver 13 that receives information, the signal reception input unit 11 uses the transmission signal from the transmitter 7 carried between the ground phase and the ground as the reception signal, and the input unit 5
1, and the input section 51 amplifies the signal attenuated by the low piezoelectric path 2. Next, the bandpass filter 53 passes a carrier carrier frequency of, for example, about 1 KHz, and removes signals and noise components in the unnecessary band. Next, the demodulation unit 55 deletes the carrier of around 1 KHz from the received signal to demodulate the timing signal, the CPU 57 reproduces arbitrary data from the information position of the timing signal, and the output I / F unit 59 is reproduced by the CPU 57. Since the optional data is output to each of the outputs 1 to 5, the receiver 1
The information received at 3 can be accurately received between the ground phase and the ground.

Next, FIG. 6 is a diagram showing a timing signal having information input to the CPU 57 of the receiver 13. First, in FIG. 6A, the CPU 57 determines the header (A) based on the elapsed time from the rising edge to the falling edge of the timing signal, and samples the timing signal after T1 seconds from the trailing edge of the header (A) as a starting point. To do. From the relationship with FIG. 4A, T1 is, for example, 1 second. The sampling result at this time is the first bit of data. Next, with T2 = 2 seconds, the timing signal is sampled, and the sampling result at this time is used as the second bit data.

As described above, if the sampling result at the time Tn seconds after the fall of the header (A) is the data of the n-th bit, the data of the received signal can be reproduced.

Further, the CPU 57 reproduces information from the timing signal demodulated by the demodulation section 55 normally, and when the reproduced information matches at least two or more, it is normally performed. By regenerating the information, the information transmitted from the transmitter 7 is transmitted to the second-class grounding grounding wire 10
You may enable it to receive correctly via.

In the above embodiment, the case where the data of the received signal is reproduced by using the sampling result of Tn seconds from the fall of the header (A) as the n-th bit data has been described, but the present invention is not limited to this. However, the present invention is not limited to this, and the data of the received signal can be reproduced even if the sampling result at Tn +2 seconds from the rising of the header (A) is used as the n-th bit data.

Next, a method of more reliably reproducing data from a timing signal having information will be described with reference to FIG. 6 (b). As shown in FIG. 6 (b), the CPU 57 causes the ΔT seconds for ± Δt seconds after Tn seconds from the fall of the header (A).
Sample the timing signal multiple times. That is,
The sampling period is Tn-Δt <sampling period <Tn + Δt.

During this 2Δt seconds, the timing signal is sampled a plurality of times, the data “0” and the data “1” in each sampling result are respectively counted, and Tn
A majority is decided by comparing the counting results at the time when + Δt seconds have passed. For example, when the data “0” = 0 and the data “1” = 3, the true data is set to “1” because the count of the data “1” is larger. Therefore, the data of the received signal can be reproduced extremely accurately.

In this way, the CPU 57 reproduces information,
Each time a predetermined time elapses from the header end position or header start position included in the demodulated timing signal, sampling is performed a plurality of times, and data is reproduced based on the majority result of the presence / absence of data, so that the transmitter 7 transmits the data. Information can be accurately received via the second-class grounding grounding wire 10.

[0043]

As described above, according to the present invention as set forth in claim 1, the transmitting section generates the timing signal in which the respective information is arranged at the information positions respectively corresponding to the plurality of information sources. , A carrier signal is generated based on the presence or absence of this timing signal and a transmission signal is generated, and this transmission signal is electromagnetically injected into the second-class grounding ground line,
The receiving unit inputs the received signal from between the ground phase and the ground at another position, demodulates the timing signal from the received signal, and then reproduces each information from the predetermined information position of the timing signal, Since the information transmitted and received between the transmitter and the receiver is accurately communicated between the ground phase and the ground, even if the amount of information to be transmitted increases, the information communication can be performed with a simple hardware / software configuration. It can be performed. Moreover, since it does not depend on the type of information, the hardware / software configuration can be versatile. Furthermore, there is no need to provide multiple carrier carrier frequencies according to the type of information,
As a result, when a carrier carrier in a normal insulation state is received, for example, a noise frequency component is added to the frequency component of the carrier carrier and converted into a frequency component in an abnormal insulation state. It is possible to prevent output. Furthermore, since a single carrier frequency is used, communication can be performed without widening the communication frequency band, and the economical efficiency of the hardware configuration can be achieved.

According to the second aspect of the present invention, the information is reproduced by sampling a plurality of times each time a predetermined time elapses from the header end position or the header start position included in the demodulated timing signal to determine whether or not there is data. By reproducing the data based on the result of the majority decision, the information transmitted from the transmitter is correctly received between the ground phase and the ground, so the data may be garbled due to the noise generated on the transport path. Is less likely to occur and the quality of the information communicated can be improved.

According to the third aspect of the present invention, the information is reproduced by reproducing a plurality of information from the demodulated timing signal, and when the plurality of reproduced information match at least two or more. Since the information is normally reproduced, the information transmitted from the transmitter is accurately received between the ground phase and the ground, so that the quality of the communicated information can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a system configuration of a ground return transportation system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of an insulation monitoring device 19 which plays a role of an information source.

FIG. 3 is a diagram showing a configuration of a transmitter 7.

FIG. 4 is a diagram showing a timing signal having information output by a CPU 43 of the transmitter 7.

FIG. 5 is a diagram showing a configuration of a receiver 13.

6 is a diagram showing a timing signal having information input to the CPU 57 of the receiver 13. FIG.

FIG. 7 is a diagram showing a system configuration of a conventional earth return transportation system.

[Explanation of symbols]

 3, 10 Second-class grounding work Grounding wire 5 Signal injector 7 Transmitter 11 Signal receiving input section 13 Receiver 41 Input I / F section 43, 57 CPU 45 Modulating section 49 Power amplifying section 51 Input section 53 Bandpass filter 55 Demodulation unit 59 Output I / F unit

Claims (3)

[Claims] 1. A transmission section electromagnetically injects information from an information source into a second-type grounding grounding wire of a low-piezoelectric path for carrying, while receiving the information carried to another position on the low-piezoelectric path. In the earth return transportation method in which the section receives from the ground phase and the earth, in the transmission section, the input information from the plurality of information sources is arranged at the information position on the timing signal according to the input number, and the carrier carrier Is generated based on the presence or absence of information on the timing signal, and the transmission signal is electromagnetically injected into the second-class grounding grounding wire, while the receiving unit grounds at the different position. A ground return transportation system characterized in that a received signal is input between the phase and the ground, a timing signal is demodulated from the received signal, and then each information is reproduced from a predetermined information position of the timing signal. 2. The reproduction of the information is performed a plurality of times each time a predetermined time elapses from the header end position or the header start position included in the demodulated timing signal, and the data is sampled based on the majority result of the presence or absence of data. The earth return transportation system according to claim 1, wherein the earth return transportation method is performed. 3. The reproduction of the information means that a plurality of pieces of information are reproduced from the demodulated timing signal, and if the plurality of pieces of reproduced information match at least two or more pieces, it means that the pieces are reproduced normally. The earth return transportation system according to claim 1, wherein