CN1276654A - Communication system for ultra-low-frequency and ultra-narrow-band distribution network - Google Patents
Communication system for ultra-low-frequency and ultra-narrow-band distribution network Download PDFInfo
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- CN1276654A CN1276654A CN 00113862 CN00113862A CN1276654A CN 1276654 A CN1276654 A CN 1276654A CN 00113862 CN00113862 CN 00113862 CN 00113862 A CN00113862 A CN 00113862A CN 1276654 A CN1276654 A CN 1276654A
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Abstract
An ultralow-frequency ultranarrow-band communication system over electric distribution network is disclosed. A receiver is installed at transformer station. Multi-channel transmitter is installed at user terminals of distribution transformer. The information in modulated current mode is transmitted from downstream to upstream over distribution network.The Frequency is lower than 100 Hz. The frequency band is lower than 0.01 Hz. The 50 Hz AC is used as reference common carrier, which is sampled and divided in frequency to obtain subcarrier. The data signals are used to modulate subcarrier, which is then used to modulate carrier. Its advantages are high anti-interference power, low transmitting power and high communication capacity.
Description
The present invention relates to communication technical field, a kind of specifically power distribution network communication system that utilizes the ultra-low-frequency and ultra-narrow-band technology
In electric power system, because the popularity that circuit distributes in the power distribution network, make that utilizing the power distribution network to carry out transfer of data becomes and measure one of valid approach of water, electricity, gas data and control load, also be a kind of most economical method easily.Fig. 4 is exactly the rough schematic of a distribution network, and in this system, high-tension line is meant the circuit that 10KV is above, and medium-voltage line and low-voltage circuit are meant 10KV and 0.4KV circuit.The high frequency carrier communication of the present widespread usage of electric power system is in the high-voltage line highway section.Also can be applicable to the low-voltage line highway section.Its communication means extensively adopts high frequency carrier (50K-500KHz) communication law, and this method is mainly used on the electric power transmission network.Its principle is to utilize method transmission information such as medium-high frequency carrier fm or phase modulation on power circuit.The passage two ends are carried out modulation and demodulation respectively by transmitter and receiver, on transmission channel equipment and relay facilities such as trap and filter will be set.In this frequency range, circuit has higher impedance.Carrier signal is propagated in the mode of voltage, and more loss is arranged on long line, because frequency is higher, cross interference is serious between each phase, and frequency can not be mutually multiplexing at each.Go up because impedance is mated easily, property difference is little at power transmission lines (high-tension line), though can by transformer the time,, therefore must set up interconnecting device and could pass through than reliable transmission because the high-frequency signal decay is very big.Because on the power distribution network, the hf channel property difference of power circuit is very big, and for the same line road, its characteristic also presents time variation, the promptly different periods, property difference is very big.Therefore, the power distribution network is a kind of channel of very severe for high-frequency carrier signal.Because its node is numerous, load is many, interference source distribution randomness is big, make high-frequency carrier signal be difficult to transmission effectively.Although utilize spread spectrum can improve its signal to noise ratio and anti-fading property, but do not reach level preferably.In general, if reasonable technology can be just all well and good in the distance that can transmit on the power distribution network about 500 meters.Want to make transmission range to strengthen again relay point must be set, and can not pass through transformer, the collection concentrator must be set in the platform district.As seen, utilize medium-high frequency carrier communication method on distribution network, to communicate by letter and to adapt to short distance and the not high place of reliability requirement.And can not to numerous, widely distributed data source carry out long-range, highly reliable, gather and transmission cheaply.
The objective of the invention is to propose a power distribution network communication system that utilizes the ultra-low-frequency and ultra-narrow-band technology, can remote transmission to reach, resist in the ability of disturbing by force, signal can pass through transformer, and sends, receives the effect of several thousand road signals simultaneously.
One of technical scheme that realizes the object of the invention is to adopt the ultralow frequency range of communications band below 100Hz.This is a zone that other technologies do not relate to.The transmission of 50Hz industrial-frequency alternating current designs owing to the power distribution net is based on, and therefore, signal can pass through distribution transformer smoothly on this frequency range, and need not relay facility, and Route Length and power factor compensation capacitance are almost to not influence of signal transmission.And cross interference is minimum between each phase, and a frequency can be heterogeneous multiplexing.In ultralow frequency range, noise occurs in every way.Usually high-frequency noise is caused by switch, brush etc., and low-frequency noise is then mainly produced by induction machine or unbalanced load motor.These noises can make it minimum by special filtering and modulation-demo-demodulation method.Because the speed of data communication is accelerated with the increase of bandwidth, improve speed so can take bigger bandwidth at the medium-high frequency segment signal, but because, the noise power of electromagnetic interference also increases linearly with the increase of bandwidth on the power transmission line, thereby broadband signal just need overcome this The noise by the power bigger than narrow band signal when transmission.When signal transmits, just can obtain big signal to noise ratio with a minimum power in an extremely narrow bandwidth.Two of technical solution of the present invention is to adopt the super arrowband technology of bandwidth below 0.01Hz to carry out data communication.In one several hertz narrow-band, can transmit several thousand tunnel signal simultaneously.Every road signal sends on the power line after same carrier modulation, by the receiving-member demodulation and isolate each road signal, converts data message to.Whole power distribution network communication system, mainly by the power distribution net, receiver, transmitter is formed.The power distribution net is a constant voltage supply network, and it is as the communication medium of native system.Transmitter is set to several, is installed in arbitrary terminal node place of distribution network respectively, because signal passes through distribution transformer, receiver can be installed in transformer station's one-level, receives the data that thousands of many transmitters send; The multichannel transmitter can send data simultaneously, and each road transmitter engages with power line by power line coupler, is connected in parallel in the loop, power supply is provided but also upstream sends information to the loop in the mode that sends modulated current signal not only for the work of self.
The means of communication of this system are characterised in that, communications band is selected the ultralow frequency range below 100Hz for use, carry out the power line data communication, the bandwidth of this data communication selects for use the following super arrowband technology of 0.01Hz to carry out, transmission information adopts the mode that is upstream sent current signal by the downstream of power distribution net, adopting with the 50Hz industrial-frequency alternating current in transmitter is the common carrier of benchmark, 50Hz industrial-frequency alternating current sampling frequency division is obtained subcarrier, sending modulation adopts earlier with the data signal modulation subcarrier again by the mode of sub-carrier modulation carrier wave, and in one several hertz narrow-band, transmit several thousand tunnel signal simultaneously, every road signal sends on the power line after same carrier modulation, come restore data by receiver with the method for hierarchical de-modulating again, promptly use method reinserted subcarrier from carrier wave of analog demodulator earlier, re-use DSP demodulating data from subcarrier, and with the 50Hz industrial-frequency alternating current as the reference signal, use digital signal processor DSP that subcarrier signal is carried out spectrum analysis, digital filtering and correlation demodulation, isolate each road signal, convert data message to.
The present invention is owing to utilize ultralow frequency, super arrowband technology, thereby compares with existing high frequency carrier communication law, has following advantage:
1. transmission range is not subjected to the restriction of line length and distribution transformer, can carry out remote transmission on distribution network smoothly.
2. antijamming capability is extremely strong.
3. transmitting power is extremely low, can be limited within several mW.
4. can send, receive several thousand tunnel signal simultaneously.
Describe structural principle of the present invention in detail below in conjunction with paying figure
Fig. 1 is a system construction drawing of the present invention
Fig. 2 is a transmitter schematic diagram of the present invention
Fig. 3 is a receiver theory diagram of the present invention
Fig. 4 is the distribution network schematic diagram
With reference to Fig. 1, system of the present invention is mainly by the power distribution net, receiver, and transmitter is formed.Wherein, the power distribution net is a constant voltage supply network, it is distribution transformer, transmitter is set to several, be installed in arbitrary terminal node place of distribution network respectively, receiver is set to one, is installed in transformer station's one-level, and this receiver can receive the data that several thousand transmitters sent that its downstream disposes.
With reference to Fig. 2, transmitter of the present invention is mainly by power line coupler, and the PM modulator is the frequency divider of benchmark with 50HZ, the FSK modulator, and the original data signal generator is formed
This transmitter adopts the method for hierarchical modulation, promptly modulate a ultra-low frequency subcarrier earlier by original data signal generator and FSK modulator, frequency range is 1～12.5Hz, and each road transmitter has all defined a specific frequency bandwidth and had only channel below the 0.01Hz in this subcarrier frequency range.This subcarrier enters the PM modulator again, carrier wave with a low frequency of analogue phase modulation method modulation, in order to realize unified frequency reference, be beneficial to the demodulation of super narrow band signal, employing is the frequency divider of benchmark with 50HZ, and its carrier wave uses with the common carrier of 50Hz industrial-frequency alternating current as benchmark, and subcarrier uses the 50Hz industrial-frequency alternating current, obtain the super narrow band signal of bandwidth less than 0.01Hz through the over-sampling frequency division, promptly subcarrier is a frequency division multiplexing.So just can in the bandwidth of a 1～12.5Hz, transmit several thousand road signals simultaneously, and not disturb mutually.Transmitter adopts the two-stage modulation, and wherein, first order modulation is the digital signal modulated analog signal, adopts the mode of FSK or ASK, and second level modulation is the analog signal modulated analog signal, can adopt the mode of phase modulation PM, modulating FM or amplitude modulation AM to realize.Sending into power couplers through the signal of second level modulation sends on the power circuit.The speed that this transmitter sends data is very low, and a data bit needs more than 30 minutes.The multichannel transmitter can send data simultaneously.Each road transmitter engages with power line by power line coupler, is connected in parallel in the loop, power supply is provided but also sends modulated current signal to the loop not only for the work of self.
With reference to Fig. 3, receiver of the present invention is by the noise beyond band pass filter (1) the elimination sideband, fully suppress load disturbance and electromagnetic interference on the power line, the phase demodulator (2) through simulating recovers subcarrier signal and carrier signal is suppressed fully then.Adjust to suitable level through buffer amplifier (3) again, send into A/D converter (4), be converted to digital signal.Digital signal processor (5) is the key of this receiver, processing to super narrow band signal, can't realize with common analogy method, can only be on the basis of high accuracy spectrum analysis with digital signal processor, the method for carrying out digital filtering and correlation energy accent realizes.Because each road transmitter has all been determined unique frequency, and this frequency is obtained by the 50Hz frequency division, therefore signal has good correlation, carries out relevant as the reference signal with handled signal the 50Hz frequency after over-sampling is sent into the DSP frequency division simultaneously in receiver.It need be gathered for a long time to subcarrier signal, processing, computing, just can finish the explanation of bandwidth being had only the signal below the 0.01Hz.Data after its demodulation send into special microprocessor store, show, print or with communicating by letter that other computers carry out.Thereby finish whole super narrow band signal and receive processing procedure.
Claims (4)
1. power distribution network communication system that utilizes the ultra-low-frequency and ultra-narrow-band technology, mainly by transformer station, the power distribution net, receiver, transmitter is formed, and the power distribution net is a constant voltage supply network, it is distribution transformer, transmitter is set to several, is installed in arbitrary terminal node place of distribution network respectively, it is characterized in that:
(1) receiver is installed in transformer station's one-level, receives the data that thousands of transmitters sent;
(2) the multichannel transmitter is arranged on the downstream of power distribution net, upstream sends data-signal simultaneously in the mode of modulated current signal, and this signal can pass through distribution transformer and be transferred to transformer station.
2. communication system according to claim 1, it is characterized in that transmitter is mainly by power line coupler, the PM modulator, with 50HZ is the frequency divider of benchmark, the FSK modulator, the original data signal generator is formed, by 50Hz industrial-frequency alternating current sampling frequency division is obtained super narrowband subcarriers signal, by original data signal this negative carrier is carried out the FSK modulation, subcarrier signal through ovennodulation enters the PM modulator again, carrier wave is carried out analog-modulated, and the signal of PM modulator output is sent into power line coupler and is sent on the power line.
3. communication system according to claim 1, it is characterized in that receiver is by band pass filter, phase demodulator through simulation, the subcarrier buffer amplifier, the A/D converter, digital signal processor DSP is formed, by the noise beyond the band pass filter elimination sideband, suppress load disturbance and electromagnetic interference on the power line, phase demodulator through simulation recovers subcarrier signal then, adjusts level through the subcarrier buffer amplifier again, sends into the A/D converter and is converted to digital signal, send into digital signal processor DSP at last, subcarrier signal is carried out spectrum analysis, digital filtering and correlation demodulation.
4. utilize the power distribution network means of communication of ultra-low-frequency and ultra-narrow-band technology, it is characterized in that communications band selects the ultralow frequency range below 100Hz for use, carry out the power line data communication, the bandwidth of this data communication selects for use the following super arrowband technology of 0.01Hz to carry out, the mode that transmission information adopts the downstream by the power distribution net upstream to send, adopting with the 50Hz industrial-frequency alternating current in transmitter is the common carrier of benchmark, 50Hz industrial-frequency alternating current sampling frequency division is obtained subcarrier, sending modulation adopts earlier with the data signal modulation subcarrier again by the mode of sub-carrier modulation carrier wave, and in one several hertz narrow-band, transmit several thousand tunnel signal simultaneously, every road signal sends on the power line after same carrier modulation, come restore data by receiver with the method for hierarchical de-modulating again, promptly use method reinserted subcarrier from carrier wave of analog demodulator earlier, re-use DSP demodulating data from subcarrier, and with the 50Hz industrial-frequency alternating current as the reference signal, use digital signal processor DSP that subcarrier signal is carried out spectrum analysis, digital filtering and correlation demodulation, isolate each road signal, convert data message to.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 00113862 CN1131605C (en) | 2000-07-07 | 2000-07-07 | Communication system for ultra-low-frequency and ultra-narrow-band distribution network |
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| Application Number | Priority Date | Filing Date | Title |
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| CN 00113862 CN1131605C (en) | 2000-07-07 | 2000-07-07 | Communication system for ultra-low-frequency and ultra-narrow-band distribution network |
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| Publication Number | Publication Date |
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| CN1276654A true CN1276654A (en) | 2000-12-13 |
| CN1131605C CN1131605C (en) | 2003-12-17 |
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| CN 00113862 Expired - Fee Related CN1131605C (en) | 2000-07-07 | 2000-07-07 | Communication system for ultra-low-frequency and ultra-narrow-band distribution network |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106253951A (en) * | 2016-09-05 | 2016-12-21 | 国家电网公司 | The suppression interference method of signal, equipment and power information acquisition system |
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- 2000-07-07 CN CN 00113862 patent/CN1131605C/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106253951A (en) * | 2016-09-05 | 2016-12-21 | 国家电网公司 | The suppression interference method of signal, equipment and power information acquisition system |
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| CN1131605C (en) | 2003-12-17 |
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