WO2012139491A1 - Long-distance high-speed broadband power line communication method - Google Patents

Abstract

The present invention relates to a broadband communication method, specifically a 35 kV voltage-rating power line-based long-distance high-speed broadband power line communication method. In the method, a power line communication device is installed on a power line, a signal is coupled by wire to the power line, then a wireless carrier signal is transmitted to space on the basis of the characteristic of a high-voltage power line, and finally a wireless signal is received wirelessly. Technical staff of the present invention solves a technical prejudice of the field. By employing the concept of using the power line as an antenna, the power line is used directly for transmission, and a wireless scheme is used for reception to receive the wireless signal transmitted by the power line antenna, thus successfully and effectively expanding communication distance to over eight kilometers, and allowing single-level relay broadband power line communication of 14.5 km.

Description

 Long-distance high-speed power line broadband communication method Technical field

 The invention relates to a broadband communication method, in particular to a long-distance high-speed power line broadband communication method based on a 35kV voltage level line.

 Background technique

The high-voltage power line broadband communication technology can establish the dedicated data channel of the power system, which has the advantages of convenience, quickness, low input cost and simple engineering construction. High-voltage power line communication only needs to install high-voltage power line communication equipment at both ends of the high-voltage power line, which makes communication on the high-voltage power line convenient and feasible. In the prior art, the long-distance high-speed power line broadband communication method adopted is to wire-connect the transmitting end and the receiving end of the power communication device with the high-voltage power line of the communication, and perform wired transmission and wired reception. However, the main problem of the power line is the distributed capacitance of the transmission line to the ground. The capacitance of 35kV to ground is large, and its influence on the signal plays a role in attenuation. At the same time, as the distance increases, the distributed capacitance increases continuously, and the attenuation increases, which will cause interruption in long-distance communication, especially the power communication carrier. Often used 1MHZ-30MHZ band. After calculation, the basic attenuation reaches 70dB within 2 km on the 35kV line. . Therefore, due to the influence of the distributed capacitance of the high-voltage line, it is difficult to achieve communication over a long distance. The prior art and practice show that with the original communication method, the farthest communication distance that can be achieved between two adjacent power communication devices is only 1.8 km. , only for medium voltage 10kV distribution network, at 35kV The communication distance on the power line of the voltage level is shorter. Such communication distance cannot meet the needs of power system communication development. The low-speed carrier transmission system can realize communication, but its transmission speed cannot meet the requirements of power system communication work; if the carrier's transmission channel is rented, it will bring extreme to safety production. Big hidden dangers.

 Summary of the invention

 The object of the present invention is to overcome the deficiencies of the prior art, and to provide a long-distance high-speed power line broadband communication method with long communication distance and fast transmission speed. .

 The present invention is achieved by the following means:

 The method for long-distance high-speed power line broadband communication has the following steps:

 Providing a power line of 35kV voltage level;

A power communication device is provided, comprising: a transmission interface, a data processing module, a signal transmitting device and a signal receiving device, wherein the transmission interface is a terminal connection interface, which is connected to the data processing module, and the transmitting end of the data processing module is connected to the signal sending device The receiving end is connected to the signal receiving device;

 The signal transmitting device of the power communication device is connected to the 35kV voltage level power line through the coupling device.

 The signal receiving device is a wireless receiving device, and an output end thereof is connected to the data processing module.

When the power carrier transmits on the line, it propagates to the space under the action of the high-voltage power line electric field, and the signal receiving device in the power communication device on the line receives the carrier signal propagating from the power line to the space through the wireless receiving mode.

 The received signal is sent to the data processing module via the wireless receiving device for processing, and transmitted to the computer terminal via the transmission interface.

In the prior art, since power communication devices are installed close to power lines, in the technical field of the prior art, for a period of several decades, those skilled in the art believe that the short-distance connection uses a wired connection. It can make the signal spread better and farther. Therefore, the power carrier communication often uses a wired method to couple the signal to the power line for transmission and receive the signal in a wired manner. 35kV On the power line of the voltage level, the signal is affected by the high frequency communication and the attenuation of the line distribution capacitance, and the ideal propagation distance cannot be achieved. The technician of the present invention overcomes the prejudice of the technology and changes the wired transmission method of power line communication to the wired transmission wireless receiving method. Through a large number of practice and research, the wireless receiving can enable the adjacent two power communication devices on the high voltage line. Communication distance can be reached 14.5km because at 35kV When a signal is transmitted on a power line of a voltage level, the carrier propagates to the space under the electric field of the high-voltage power line, and the attenuation is small and the propagation distance is long. Therefore, under the condition that the cable transmits the power carrier signal on the high-voltage line, the wireless reception can greatly increase the power communication. Distance to achieve long-distance high-speed power broadband communication.

 The invention can be further specifically:

The signal transmitting device comprises a power modulation module, a power carrier transmitting module and a power carrier sampling module, wherein the input end of the power modulation module is connected to the data processing module, and the power carrier sampling module is connected to the power carrier sampling module. On a 35kV voltage class power line,

After the power modulation module is modulated, it is processed by the power carrier transmitting module, and the power carrier sampling module samples the power carrier from the power carrier transmitting module, and then loads the sampled power carrier into the 35kV through the coupling device. Voltage level on the power line.

The signal receiving device comprises a power demodulation module, a carrier sampling module, a wireless receiving module and an antenna connected in sequence, and an output of the power demodulation module is connected to the data processing module.

The signal diverging into the space under the action of the electric field on the high-voltage power line enters the wireless receiving module via the antenna, and the carrier sampling module extracts the signal carrier from the wireless receiving module, and then sends it to the power demodulation module for demodulation, and finally sends it to the data processing module for analysis and processing. And then transmitted to the terminal.

 The data processing module adopts orthogonal frequency division multiplexing technology, and includes an orthogonal frequency division multiplexing processing chip.

 Orthogonal Frequency Division Multiplexing (OFDM for short) The technology uses multiple narrow-band orthogonal subcarriers to simultaneously transmit multiple channels of data, and each symbol has a longer symbol time, which can avoid inter-symbol interference. By dynamically selecting the available subcarriers, this technique can reduce the effects of narrowband interference and frequency valleys.

 In addition, OFDM technology can improve the quality of power line network transmission, even in the case of severe interference in the distribution network, OFDM It also provides high bandwidth and guarantees bandwidth transfer efficiency, and with proper error correction technology ensures reliable data transmission. In OFDM The carriers of each subchannel in the system are orthogonal to each other, so that their spectrums overlap each other, which not only reduces mutual interference between subcarriers, but also improves spectrum utilization, and can also resist equal amplitude interference. But OFDM The reception is complex, costly and sensitive to transient disturbances. High-speed power line communication mainly uses OFDM technology.

 The data processing module of the present invention processes the signal address when transmitting data as follows:

After receiving the data packet from the terminal, first determining whether the data packet has a default address, and if the default address, saving the data packet or returning the data packet;

 If the data contains an address, it is determined whether the address is a local address, and if so, the data packet is processed and ready to be transmitted;

 The data processing module of the present invention processes the signal address when receiving data as follows:

 After receiving the wireless carrier signal from the power line, first determining whether the address in the data packet is a local address, and if not, discarding the data packet;

 If the address in the packet is a local address, decryption processing is performed and transmitted to the terminal.

 The invention may further be specifically:

 The coupling device is either an inductive coupler or a capacitive coupler.

According to the current domestic power grid architecture and through a large number of field tests, it is ideal to use inductively coupled sampling signals for buried cables, and it is ideal for capacitive coupling signals for overhead cables. Since the high voltage line of the present invention is generally an overhead cable, it is preferable to select a capacitive coupling sampling method.

In addition, the coupling device also functions as a safety isolation. The inductive coupler is used for the buried high-voltage cable. The inductive coupler is coupled to the insulated cable and does not directly contact the power line. The high-frequency signal is obtained by induction, and the inductive coupler With a full grounding point. For high-voltage cables with overhead, high-frequency capacitive couplers are used to take signals from the low-voltage end. The capacitive couplers are equipped with reliable grounding and lightning protection technology, which is safe and reliable.

 In summary, the present invention provides a long-distance high-speed power line broadband communication method based on 35 kV A voltage level power line, the power communication device is mounted on the power line, the signal is coupled to the power line in a wired manner, and then the wireless carrier signal is propagated to the space according to the characteristics of the high voltage power line, and finally the wireless signal is received in a wireless manner. . The technician of the present invention overcomes the technical prejudice in the art, adopts the idea of using a power line as an antenna, transmits a direct use power line, receives a wireless signal transmitted by a power line antenna by using an antenna, and successfully and effectively extends the communication distance to 8 kilometers. In the above, the first-line relay 14.5KM power line broadband communication is realized.

 DRAWINGS

 1 is a block diagram showing the communication principle of the long-distance high-speed power line broadband communication method according to the present invention;

 2 is a schematic diagram showing the circuit principle framework of the long-distance high-speed power line broadband communication device according to the present invention;

 The invention will be further described below in conjunction with the accompanying drawings.

 Specific embodiment

 Best embodiment:

 Referring to Figure 1, a long-distance high-speed power line broadband communication method includes the following steps:

 Providing a power line of 35kV voltage level;

Provided is a long-distance power line broadband communication device (hereinafter referred to as a power communication device), which comprises a transmission interface, a data processing module, a signal transmitting device and a signal receiving device, and the transmission interface is a terminal connection interface, which is connected to the data processing module;

The signal transmitting device of the power communication device includes a power modulation module, a power carrier transmitting module, and a power carrier sampling module, wherein the input end of the power modulation module is connected to the data processing module, and the power carrier sampling module is connected to the power device through the coupling device. On a 35kV voltage class power line,

The signal from the data processing module is modulated by the power modulation module and processed by the power carrier transmitting module. The power carrier sampling module samples the power carrier from the power carrier transmitting module, and then loads the sampled power carrier through a capacitive coupler. On the power line of 35kV voltage level;

The signal receiving device is a wireless receiving device, comprising a power demodulation module, a carrier sampling module, a wireless receiving module and an antenna connected in sequence; and an output end of the power demodulation module is connected to the data processing module;

After the power carrier is transmitted to the high-voltage line and transmitted to the space under the action of the high-voltage power line electric field, the signal receiving device in the power communication device on the line receives the carrier signal propagating from the power line to the space through the wireless receiving mode, and the signal passes through the antenna. After entering the wireless receiving module, the carrier sampling module extracts the signal carrier from the wireless receiving module, and then sends it to the power demodulation module for demodulation.

 Finally, it is sent to the data processing module for processing and sent to the computer terminal via the transmission interface.

 The core chip of the data processing module of the power communication device adopts the US INTELLON company 85M and 200M. The power line communication chip, which uses OFDM modulation technology, is the world's most advanced power line communication chip. For high transmission rate access networks, multi-carrier orthogonal frequency division multiplexing (OFDM) Technology is considered to be the most appropriate technical solution. OFDM The data is modulated by a plurality of mutually orthogonal carriers, and the serial data stream is converted into parallel processing. It has high channel utilization close to the Shannon limit; and it can effectively resist multipath effects, solve inter-symbol crosstalk problems, and has strong anti-burst interference capability; in addition, in channel allocation, OFDM also offers the possibility of flexible operation to circumvent deep fading bands within the communication bandwidth; OFDM technology in high-speed PLCs Widely used in applications. The orthogonal frequency division multiplexing technology uses multiple narrow-band orthogonal subcarriers to simultaneously transmit multiple channels of data, and each symbol has a longer symbol time, which can avoid inter-symbol interference. By dynamically selecting the available subcarriers, this technique can reduce the effects of narrowband interference and frequency valleys.

 OFDM technology can also improve the quality of power line network transmission, even in the case of severe interference in the distribution network, OFDM It provides high bandwidth and guarantees bandwidth transmission efficiency, and the use of appropriate error correction technology ensures reliable data transmission. In OFDM The carriers of each subchannel in the system are orthogonal to each other, so that their spectrums overlap each other, which not only reduces mutual interference between subcarriers, but also improves spectrum utilization, and can also resist equal amplitude interference.

 OFDM The technique uses a discontinuous multi-tone technique to combine a large number of signals in different frequencies, called carriers, into a single signal to complete the signal transmission. Since this technology has the ability to transmit signals under clutter interference, it is often used in transmission media that are susceptible to external interference or poor resistance to external interference.

 The receiving end of the signal receiving device of the power communication device is directly connected to the antenna, and can be designed according to standard wireless communication.

 The communication method of the present invention will be further described below by way of an example:

1. Provide a 35kV voltage class power line, including A substation and B substation;

2. Providing a power communication device as High-voltage power communication equipment (power bridge), between the A substation and the B substation, realizes modulation and demodulation between the Ethernet signal and the carrier signal through the high-voltage power bridge.

3, The high-voltage capacitive coupler uses a capacitive coupler. The function of the high-voltage power communication device is to modulate the Ethernet signal into a carrier signal. The function of the coupler is to load the carrier signal into the connected device on the power grid.

4, High-voltage power communication equipment is installed in the A substation and the B substation. The installation method is that the WAN port of the device is connected with the upper layer of the power communication network, and the PLC port is connected with the high-voltage capacitive coupler by the coaxial cable, the capacitive coupler and the high voltage. The grid is connected. The power supply of the high-voltage power communication equipment can be led to the commercial power in the substation. The WAN port of the high-voltage power communication device can be interconnected by an optical fiber and a power communication network (terminal LAN).

5, 35KV There is no ground line and center line on the line, so the B phase is used as the virtual center line; because the line distance is long, the transmission and reception lines are separated, the transmission signal is to be amplified by wide frequency, the signal transmission transmission circuit is AB phase, and the signal receiving wireless transmission circuit is adopted. Wireless, three high-frequency coupling capacitors need to be installed at each signal point, in which the B-phase high-frequency coupling capacitor is grounded as a virtual center point, and the A and C are connected as a transmission line.

6. The capacitive coupler is installed at the outlet point of the substation and the overhead line of the relay position.

 The parts not described in the present invention are the same as those in the prior art.

Claims (7)

1.  A long-distance high-speed power line broadband communication method, characterized in that the method comprises the following steps:

   Providing a power line of 35kV voltage level;

   A power communication device is provided, comprising: a transmission interface, a data processing module, a signal transmitting device and a signal receiving device, wherein the transmission interface is a terminal connection interface, which is connected to the data processing module, and the transmitting end of the data processing module is connected to the signal sending device The receiving end is connected to the signal receiving device;

   The signal transmitting device of the power communication device is connected to the 35kV voltage level power line through the coupling device.

   The signal receiving device is a wireless receiving device, and an output end thereof is connected to the data processing module.

   When the power carrier transmits on the line, it propagates to the space under the action of the high-voltage power line electric field, and the signal receiving device in the power communication device on the line receives the carrier signal propagating from the power line to the space through the wireless receiving mode.

   The received signal is sent to the data processing module via the wireless receiving device for processing, and transmitted to the computer terminal via the transmission interface.
2. According to claim 1 The remote high-speed power line broadband communication method is characterized in that: the signal sending device comprises a power modulation module, a power carrier transmitting module and a power carrier sampling module, which are sequentially connected, wherein the input end of the power modulation module and the data processing module Connected, the power carrier sampling module is connected to the coupling device On the 35kV voltage class of the power line.
3. According to claim 1 The long-distance high-speed power line broadband communication method is characterized in that: the signal receiving device comprises a power demodulation module, a carrier sampling module, a wireless receiving module and an antenna, and an output end of the power demodulation module and a data processing module. connection.
4. According to claim 1 The remote high-speed power line broadband communication method is characterized in that the data processing module adopts an orthogonal frequency division multiplexing technology, and includes an orthogonal frequency division multiplexing processing chip.
5. The long-distance high-speed power line broadband communication method according to claim 1, wherein The data processing module processes the signal address when sending data as follows:

   After receiving the data packet from the terminal, first determining whether the data packet has a default address, and if the default address, saving the data packet or returning the data packet;

   If the data contains an address, it is determined whether the address is a local address, and if so, the packet is processed and ready for transmission.
6. According to claim 1 The long-distance high-speed power line broadband communication method is characterized in that: the data processing module processes the signal address when receiving the data as follows:

   After receiving the wireless carrier signal from the power line, first determining whether the address in the data packet is a local address, and if not, discarding the data packet;

   If the address in the packet is a local address, decryption processing is performed and transmitted to the terminal.
7. The long-distance high-speed power line broadband communication method according to claim 1, wherein The coupling device is either an inductive coupler or a capacitive coupler.

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