A high-voltage transmission line sharing tower conductor power supply system and calculation method

Abstract

The present invention belongs to the technical field of high-power power supply from high-voltage transmission lines, and specifically relates to a power supply system and calculation method for high-voltage transmission lines sharing iron tower conductors. In view of the shortcomings of the existing high-voltage transmission line iron tower conductor power supply system that is not suitable for 5G communication, the present invention adopts the following technical scheme: a high-voltage transmission line sharing iron tower conductor power supply system of the present invention, the power supply system includes: a transformer, the primary side of the transformer is connected to the transmission line of the high-voltage transmission line, and the secondary side of the transformer outputs 220V AC; a machine room, the machine room is provided with a voltage change device; a load device; the load device includes an active antenna unit; the secondary side of the transformer is connected to the input end of the voltage change device, and the output end of the voltage change device is connected to the active antenna unit. The high-voltage transmission line iron tower conductor power supply system of the present invention realizes iron tower sharing, and the power supply is reliable and stable.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-power power extraction from high-voltage transmission lines, and specifically relates to a power extraction system for high-voltage transmission lines sharing iron tower conductors, which can be used for power supply of 5G communication base stations. The present invention also relates to a method for calculating the antenna hanging height or coverage radius. Background Art

[0002] my country is currently in an era of "post-4G" and the beginning of 5G, and all of this requires the support of a large, fully covered wireless communication network. Compared with 4G signals, 5G signals have been comprehensively improved in terms of speed, latency and other aspects, but the signal coverage of a single base station is relatively small. If 5G signals are to be fully covered, a large number of towers equipped with antennas are bound to be required.

[0003] 5G-related communication equipment has the following upgrades compared to old equipment:

[0004] (1) Active Antenna Units (AAU) mounted on towers need to be added because 5G uses new frequency bands based on old frequency bands, while existing communication equipment will continue to be used.

[0005] (2) Cabinets may need to be added or replaced. The baseband processing unit (BBU) of 5G communication technology is more powerful than its predecessor, but also consumes more power. This requires the cabinet to provide additional space to carry the BBU (baseband processing unit) and dissipate heat.

[0006] (3) More integrated equipment. In traditional communication base stations, antennas and remote radio units (RRUs) are connected by feeder lines. The Massive MIMO technology used in 5G communication technology has led to the integration of large-scale antenna arrays and RRUs into active antenna units (AAUs).

[0007] "Shared towers" are, as the name implies, the installation of communication base stations on the overhead transmission line towers of the power system. However, the high power consumption of base stations has challenged the existing power supply technology. The upgrading of equipment has also greatly increased the power consumption of macro base stations. If a tower is selected to set up a base station to serve three communication operators, each communication operator needs three AAUs, and the power of one AAU is 5kW, then the power of the base station here will reach at least 45kW.

[0008] The increase in power has also put forward high requirements for the power supply method. The power supply method for communication equipment on the power tower needs to ensure that the power output of the power supply is not affected by grid current fluctuations and environmental changes, and can ensure stable power output. It must also be as small as possible, light in weight, safe, environmentally friendly and easy to install. At present, the main power supply methods for high-voltage lines are current transformer power supply, voltage transformer power supply, and wireless power transmission.

[0009] Current transformer induction power is the most studied high-voltage power supply method. Using the principle of electromagnetic induction, current transformers also have significant disadvantages: First, when the current flowing through the transmission line is relatively small or even when the transmission circuit is unloaded and the current is zero, the output power of the power supply circuit is insufficient; second, when the current flowing through the transmission line is relatively large and exceeds the rated current of the transformer coil, especially the short-circuit current, the power supply CT is severely saturated and the power supply device is seriously heated. The voltage transformer converts the high voltage into a low voltage that can be directly used by the measurement or relay protection device by converting the voltage, but due to the limitations of measurement accuracy and cost requirements, the capacity of the voltage transformer is generally only tens of volt-amperes, and the output energy is limited. Even at a low supply voltage, wireless power transmission can generate a large current due to resonance, thereby establishing a strong electromagnetic field. However, there are too many factors affecting wireless power transmission, such as high-frequency power supply, coil material, coil withstand voltage, coil orientation, etc., especially the power limitation caused by the coil withstand voltage problem.

[0010] The existing power supply methods cannot meet the high power consumption requirements of 5G base stations. To solve the problem of high-power power supply for 5G base stations, a power supply method is needed that can not only provide sufficient power to the base station, but also be reliable in terms of power supply safety and stability, and can ensure the normal operation of the base station. Summary of the invention

[0011] Aiming at the insufficiency of the existing high-voltage transmission line shared tower wire power supply system being unsuitable for 5G communication, the present invention provides a high-voltage transmission line shared tower wire power supply system, which can provide sufficient power to the base station and is relatively reliable in terms of power supply safety and stability, and can ensure the normal operation of the base station. The present invention also provides a method for calculating the antenna hanging height or coverage radius.

[0012] To achieve the above object, the present invention adopts the following technical solution: a high-voltage transmission line shared iron tower conductor power supply system of the present invention, the power supply system comprises:

[0013] A transformer, wherein the primary side of the transformer is connected to a high-voltage transmission line, the secondary side of the transformer outputs 220V AC, and the casing of the transformer is grounded;

[0014] A machine room, wherein a voltage changing device is provided in the machine room;

[0015] A load device, the load device comprising an active antenna unit, the active antenna unit being arranged on the iron tower;

[0016] The secondary side of the transformer is connected to the input end of the voltage variation device, and the output end of the voltage variation device is connected to the active antenna unit.

[0017] The high-voltage transmission line shared tower conductor power supply system of the present invention utilizes the original transmission line towers of the power system and installs communication base stations on the overhead transmission line towers of the power system to realize tower sharing; transformers and voltage change devices are used to power the active antenna units, with large output power and reliable and stable power supply, which can provide conditions for three operators to install macro base stations at the same time.

[0018] As an improvement, the transformer is a single-phase transformer. The high-voltage transmission line is a three-phase transmission line. Usually, the transformer used in the distribution system is a three-phase transformer. Taking the 220kV high-voltage transmission line as an example, the three-phase transformer can realize the transformation from 220kV AC to 220V AC through multi-stage transformation, and then obtain 48V DC through a bridge rectifier circuit. However, the volume of the multi-stage three-phase transformer is too large. If each tower (i.e., tower) power supply system adopts a three-phase transformer, it is not suitable from the perspectives of cost, installation, and later operation and maintenance. Therefore, a transformer with a small footprint and good insulation performance is needed to replace the three-phase transformer. This application adopts a single-phase transformer with a primary input of 220kV and a secondary output of 220V. The primary and secondary turns ratio of the transformer is 1000:1. Due to the high transformation ratio of the transformer, the inter-turn insulation problem of the primary winding of the transformer should be properly solved, especially the inter-turn insulation. Compared with the design of conventional three-phase transformers, the advantage of this type of transformer is that its transformation ratio is relatively high and its size is relatively small, which can save a lot of costs in the installation and operation and maintenance of the transformer.

[0019] As an improvement, the transformer is mounted on a bracket two meters above the ground. If the transformer is placed on the ground, it may be attacked by animals and rainwater may flow back, which often causes the transformer to short-circuit. On the other hand, placing the transformer on a two-meter bracket is also convenient for later operation and maintenance.

[0020] As an improvement, the power taking system further includes a machine room air conditioner, and the secondary side of the transformer is connected to the machine room air conditioner. The machine room air conditioner is installed to ensure sufficient heat dissipation in the machine room, and the machine room air conditioner is directly powered by the secondary side of the transformer.

[0021] As an improvement, the primary side of the transformer is connected to the two-phase leads on both sides of the double-circuit iron tower. If two-phase lines are connected on the same side of the iron tower, a two-phase short circuit fault may occur in the transmission line. For safety reasons, two-phase leads should be connected on both sides of the iron tower.

[0022] As an improvement, the connection sequence of the primary side and the three-phase line of the tower when the adjacent multiple transformers are directly powered is AB, BC, CA cycle or AB, CA, BC cycle. High-voltage transmission lines generally use three-phase AC lines. If the power is directly drawn from phase A at each transmission tower, as the power continues to increase, it will cause serious three-phase imbalance in the transmission line, which will have a greater impact on the safe operation of the power grid. The three-phase imbalance phenomenon mentioned here is not the same concept as the three-phase imbalance avoided by phase change in the transmission line of the power system. The three-phase imbalance in the transmission line of the power system is due to the asymmetry of current and voltage during the normal operation of the power system, so the three-phase line is required to be phase-changed along the line. The three-phase cycle power supply principle proposed in this application is to avoid the three-phase imbalance caused by drawing power from the same phase multiple times. The direct power supply sequence of multiple adjacent transformers can also be AB, BC, CA, AB, BC, CA and other equivalent methods, as long as the number of times each phase of the transmission line draws power is close, a basic balance can be achieved.

[0023] As an improvement, the voltage variation device includes a rectifier module, a filter module and a step-down module to output 48V DC power to power the active antenna unit.

[0024] As an improvement, the rectifier module adopts a bridge uncontrolled rectifier circuit, the filter module adopts an LC circuit, and the buck module adopts a BUCK circuit involving IGBT. In other embodiments, the buck module may adopt a BUCK circuit involving MOSFET.

[0025] As an improvement, after the wire is led down from the transmission line, fuses or circuit breakers are installed according to different voltage levels and then connected to the primary side of the transformer. After the wire is led down from the transmission line, fuses or circuit breakers are installed according to different voltage levels and then connected to the primary side of the transformer, so that it can be disconnected from the transmission network in time in case of a fault without affecting the operation of the transmission network. When the voltage level of the transmission line is low at 35kV and below, a fuse should be selected. The specific model is RW5-35kV drop-out fuse, which can be installed on the branch line of the 35kV distribution line. Because it has an obvious disconnection point of a high-voltage drop-out fuse, it has the function of an isolating switch, creating a safe working environment for the maintenance section lines and equipment, and increasing the sense of security of maintenance personnel. Installed on the distribution transformer, it can be used as the main protection of the distribution transformer. When the voltage level of the transmission line is higher than 35kV, SF6 circuit breakers should be used. For SF6 circuit breakers, SF6 gas density relays and SF6 gas pressure gauges are required. A stop valve is required between the gas density relay and the body, and an accident alarm and locking operating mechanism are required. The secondary circuit of the circuit breaker should be able to prevent electromagnetic induction. The SF6 gas system of the circuit breaker should be easy to sample, install and maintain, and be equipped with a gas sampling valve and connector. The circuit breaker should have a gas supply port.

[0026] As an improvement, another line is branched from the down conductor to install a lightning arrester and ground it. Different types of lightning arresters should also be selected according to different voltage levels. When the voltage level of the transmission line is 220kV, the lightning arrester uses HY10WZ-216 / 562 220kV high-voltage lightning arrester. HY10WZ-216 / 562 220kV high-voltage lightning arrester is said to be able to perform frequent operations or multiple short-circuit current interruptions within the working current range. The mechanical life can be up to 30,000 times, and the number of short-circuit current interruptions at full capacity can reach 50 times. The 220kV high-voltage lightning arrester is suitable for reclosing operations and has extremely high operational reliability and service life. When the voltage level of the transmission line is below 220kV, the YH5WX-54 / 150 lightning arrester is used. This type of lightning arrester can be used for AC 220kV and below power generation, transmission, substation, and distribution systems to limit the amplitude of lightning and system internal operating overvoltage to a specified level.

[0027] A method for calculating the height or coverage radius of an antenna shared by a high-voltage transmission line, the method for calculating the height or coverage radius of an antenna shared by a high-voltage transmission line is applied to a power supply system shared by a high-voltage transmission line and a tower conductor, and the method for calculating the height or coverage radius of an antenna includes the following steps:

[0028] S1. Determine basic parameters of the base station antenna, where the basic parameters include transmit power, gain, and receive sensitivity.

[0029] S2. Determine the area that the base station antenna needs to cover, so as to determine the values ​​of penetration loss and interference margin;

[0030] S3. Calculate the maximum allowable path loss.

[0031] S4. Determine the antenna coverage radius (when the hanging height is known) or the antenna hanging height (when the coverage radius is known) through a signal propagation model.

[0032] As an improvement to the calculation method: In S3, the maximum allowable path loss PL MAX (dB) is calculated using the formula:

[0033] PL MAX =P Tx -L f +G Tx -M f -M l +G Rx -L P -L b -S Rx +ΔL 1 -ΔL 2 (1)

[0034] ΔL 1 =20lghBS (2)

[0035] ΔL 2 =-1.4d+20.9 (3)

[0036] P Tx is the base station transmit power, and in the uplink it is the base station receive power;

[0037] L f is the feeder loss;

[0038] G Tx is the base station antenna gain;

[0039] M f is the shadow fading and fast fading margin;

[0040] M l is the interference margin;

[0041] G Rx is the mobile phone antenna gain;

[0042] L P is the building penetration loss;

[0043] L b For human body loss;

[0044] S Rx , it is the receiving sensitivity of the mobile phone in downlink, and it is the transmitting power of the mobile phone in uplink;

[0045] d is the average tree spacing;

[0046] In S4, the antenna coverage radius (when the hanging height is known) or the antenna hanging height (when the coverage radius is known) is determined by the signal propagation model, and the calculation method is as follows:

[0047]

[0048]

[0049] Among them: PL Rma-NLOS Take it as the maximum allowable path loss (dB) obtained in formula (1);

[0050] f c is the operating frequency (GHz);

[0051] h BS is the effective height of the base station antenna (m);

[0052] h UT is the effective height of the mobile station antenna (m);

[0053] d 2Dis the straight-line distance between the base station antenna and the mobile station antenna (m);

[0054] W is the street width (m);

[0055] h is the average building height (m).

[0056] The beneficial effects of the high-voltage transmission line shared tower conductor power supply system of the present invention are: 1. This power supply method meets the operating power requirements of the macro base station, can provide sufficient power to the base station, and is relatively reliable in terms of safe and stable power supply, and can ensure the normal operation of the base station; 2. The open sharing of "power tower" and "communication tower" is of great benefit to promoting the coordinated development of power and communication infrastructure, especially for the upcoming 5G network deployment, which can be said to kill two birds with one stone. Furthermore, the combination of various technical features also has the following beneficial effects: 3. A single-phase transformer is used. Compared with the three-phase transformer in the traditional power distribution system, this power transformer has higher efficiency and smaller size, and the installation and later operation and maintenance costs are low. The capacity of the transformer can reach 50kW, which meets the power requirements of the macro base station; 4. The principle of three-phase cycle power supply is adopted to avoid the three-phase imbalance of the transmission line, and can provide a stable and continuous power supply to the base station without affecting the inherent high-voltage transmission line.

[0057] The beneficial effect of the method for calculating the hanging height or coverage radius of the antenna shared by the high-voltage transmission line tower of the present invention is: a specific set of equations is given to describe the relationship between the AAU installation height and the signal coverage range. The most suitable AAU installation height can be calculated according to the specific field factors and the required signal coverage range through the set of equations, so as to formulate a reasonable mounting plan to meet the communication requirements to the greatest extent, which not only meets the signal coverage requirements of the communication operator, but also ensures the efficient and stable transmission of the signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 It is a structural schematic diagram of a power supply system according to a first embodiment of the present invention.

[0059] Figure 2 It is a structural diagram of a power supply system according to a second embodiment of the present invention.

[0060] Figure 3 1 is a circuit diagram of a power supply system according to an embodiment of the present invention.

[0061] Figure 4 It is a schematic diagram of the 3D propagation path of a signal according to the calculation method of an embodiment of the present invention.

[0062] In the picture, 1. Iron tower,

[0063] 2. Active antenna unit,

[0064] 3. Circuit breaker,

[0065] 4. Lightning arrester,

[0066] 5. Transformer,

[0067] 6. Computer room,

[0068] 7. Ground wire,

[0069] 8. Fuse,

[0070] 9. Bracket. DETAILED DESCRIPTION

[0071] The following is an explanation and description of the technical solutions of the embodiments of the present invention in conjunction with the accompanying drawings of the embodiments of the present invention, but the following embodiments are only preferred embodiments of the present invention, not all. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without creative work are all within the protection scope of the present invention.

[0072] See also Figures 1 to 3 A high-voltage transmission line shared iron tower conductor power taking system of the present invention comprises:

[0073] A transformer, wherein the primary side of the transformer is connected to a high-voltage transmission line, the secondary side of the transformer outputs 220V AC, and the casing of the transformer is grounded;

[0074] A machine room, wherein a voltage changing device is provided in the machine room;

[0075] A load device, the load device comprising an active antenna unit, the active antenna unit being arranged on the iron tower;

[0076] The secondary side of the transformer is connected to the input end of the voltage variation device, and the output end of the voltage variation device is connected to the active antenna unit.

[0077] The development of 5G is a major trend in today's society, but since the signal coverage of existing base stations is relatively small, if 5G signals are to cover my country on a large scale, a large number of towers with antennas will inevitably be needed. "Shared towers", as the name implies, are to install communication base stations on the overhead transmission line towers of the power system, but the high power consumption of base stations has challenged the existing power supply technology. Current mutual induction, current mutual induction technology power supply and wireless power transmission technology cannot meet the stable power demand of base stations. In response to the high power consumption demand of 5G base stations, the present invention proposes a high-voltage transmission line shared tower conductor direct power supply system, which directly obtains high-power electricity from the high-voltage transmission line through a single-phase transformer, changing the traditional power supply method for electrical equipment. The high-voltage transmission line shared tower conductor power supply system of the present invention uses the original transmission line tower of the power system to install communication base stations on the overhead transmission line tower of the power system to achieve sharing; transformers and voltage change devices are used to power the active antenna units, and the power supply is reliable and stable, which can provide conditions for the three operators to install macro base stations at the same time.

[0078] Embodiment 1 of a power-taking system for high-voltage transmission lines sharing iron tower conductors

[0079] A high-voltage transmission line shared iron tower 1 conductor power supply system of the present invention, the power supply system comprises:

[0080] A transformer 5, wherein the primary side of the transformer 5 is connected to a high-voltage power transmission line, and the secondary side of the transformer 5 outputs 220V AC power. The housing of the transformer 5 is grounded 7;

[0081] A machine room 6, wherein a voltage changing device is provided in the machine room 6;

[0082] A load device, the load device comprising an active antenna unit 2, the active antenna unit 2 being arranged on the iron tower 1;

[0083] The secondary side of the transformer 5 is connected to the input end of the voltage variation device, and the output end of the voltage variation device is connected to the active antenna unit 2 .

[0084] See also Figure 1 and Figure 3As an improvement, the transformer 5 is a single-phase transformer 5. The high-voltage transmission line is a three-phase transmission line. Usually, the transformer 5 used in the power distribution system is a three-phase transformer 5. Taking the 220kV high-voltage transmission line as an example, the three-phase transformer 5 can realize the transformation from 220kV AC to 220V AC through multi-stage transformation, and then obtain 48V DC through a bridge rectifier circuit. However, the volume of the multi-stage three-phase transformer 5 is too large. If each iron tower 1 (i.e., iron tower 1) power supply system adopts a three-phase transformer 5, it is not suitable from the perspectives of cost, installation, and later operation and maintenance. Therefore, a transformer 5 with a small footprint and good insulation performance is needed to replace the three-phase transformer 5. The present application adopts a single-phase transformer 5, with a primary input of 220kV and a secondary output of 220V. The primary and secondary turns ratio of the transformer 5 is 1000:1. Since the transformer 5 has a high transformation ratio, the inter-turn insulation problem of the primary winding of the transformer 5 should be properly solved, especially the inter-turn insulation. Compared with the design of a conventional three-phase transformer 5 , the advantage of this transformer 5 is that it has a relatively high transformation ratio and a relatively small size, which can save a lot of cost in the installation and operation and maintenance of the transformer 5 .

[0085] As an improvement, the transformer 5 is mounted on a bracket 9 at a height of two meters above the ground of the iron tower 1. If the transformer 5 is placed on the ground, it may be attacked by animals and rainwater may flow back, which may cause a short circuit in the transformer 5. On the other hand, placing the transformer 5 on a bracket 9 at a height of two meters is also convenient for later operation and maintenance. The height of the bracket 9 from the ground can be higher or lower than two meters.

[0086] As an improvement, the power taking system further includes an air conditioner for the machine room 6, and the secondary side of the transformer 5 is connected to the air conditioner for the machine room 6. The air conditioner for the machine room 6 is installed to ensure sufficient heat dissipation in the machine room 6, and the air conditioner for the machine room 6 is directly powered by the secondary side of the transformer 5.

[0087] As an improvement, the primary side of the transformer 5 is connected to the two-phase leads on both sides of the double-circuit iron tower 1. If two-phase lines are connected on the same side of the iron tower 1, a two-phase short circuit fault may occur in the transmission line. For safety reasons, two-phase leads should be connected on both sides of the iron tower 1.

[0088] As an improvement, the connection sequence of the primary side and the three-phase line of the tower when the adjacent multiple transformers 5 are directly powered is AB, BC, CA cycle or AB, CA, BC cycle. High-voltage transmission lines generally use three-phase AC lines. If the power is directly drawn from phase A at each transmission tower, as the power continues to increase, it will cause serious three-phase imbalance in the transmission line, which will have a greater impact on the safe operation of the power grid. The three-phase imbalance phenomenon mentioned here is not the same concept as the three-phase imbalance avoided by phase change in the power transmission line in the power system. The three-phase imbalance in the power transmission line of the power system is due to the asymmetry of current and voltage when the power system is operating normally, so the three-phase line is required to be phase-changed along the line. The three-phase cycle power supply principle proposed in this application is to avoid the three-phase imbalance caused by drawing power from the same phase multiple times. The direct power supply sequence of the adjacent multiple transformers 5 can also be AB, BC, CA, AB, BC, CA and other equivalent methods, as long as the number of times each phase of the transmission line draws power is close, a basic balance can be achieved.

[0089] As an improvement, the voltage variation device includes a rectifier module, a filter module and a step-down module to output 48V DC power to power the active antenna unit 2.

[0090] As an improvement, the rectifier module adopts a bridge-type uncontrolled rectifier circuit, the filter module adopts an LC circuit, and the step-down module adopts a BUCK circuit involving MOSFET.

[0091] As an improvement, after the wire is led down from the transmission line, a fuse 8 or a circuit breaker 3 is installed according to different voltage levels and then connected to the primary side of the transformer 5. After the wire is led down from the transmission line, a fuse 8 or a circuit breaker 3 is installed according to different voltage levels and then connected to the primary side of the transformer 5, so that it can be disconnected from the transmission network in time when a fault occurs and will not affect the operation of the transmission network. When the voltage level of the transmission line is higher than 35kV, SF6 circuit breaker 3 is selected. For SF6 circuit breaker 3, SF6 gas density relay and SF6 gas pressure gauge device are required. A stop valve is required to be installed between the gas density relay and the body, and an accident alarm and a locking operating mechanism are required. The secondary circuit of circuit breaker 3 should be able to prevent electromagnetic induction. The SF6 gas system of circuit breaker 3 should be easy to sample, install and maintain, and equipped with a gas sampling valve and connector. Circuit breaker 3 should have a gas replenishment port.

[0092] As an improvement, a line is branched from the down conductor to install a lightning arrester 4 and ground it. Different types of lightning arresters 4 should also be selected according to different voltage levels. When the voltage level of the transmission line is 220kV, the lightning arrester 4 adopts HY10WZ-216 / 562 220kV high-voltage lightning arrester 4. HY10WZ-216 / 562 220kV high-voltage lightning arrester 4 is said to be able to perform frequent operations or multiple short-circuit current interruptions within the working current range. The mechanical life can be up to 30,000 times, and the number of short-circuit current interruptions at full capacity can reach 50 times. The 220kV high-voltage lightning arrester 4 is suitable for reclosing operations and has extremely high operational reliability and service life. When the voltage level of the transmission line is below 220kV, the YH5WX-54 / 150 lightning arrester 4 is used. This type of lightning arrester 4 can be used for AC 220kV and below power generation, transmission, substation, and distribution systems to limit the amplitude of lightning and system internal operating overvoltage to a specified level.

[0093] During the application process, the power supply system of the first embodiment of the present invention solves at least the following problems: 1. How to determine the power supply position? The direct power supply position of the high-voltage line is set at the place where the tower insulator is suspended and connected to the transmission line. 2. How to convert high voltage electricity into 220V AC and how to convert 200V AC into 48V DC? A single-phase transformer 5 is used to convert the high voltage into 220V AC, and a rectifier module, a filter module and a step-down module are used to convert 200V AC to 48V DC. 3. How to avoid the three-phase imbalance problem that may be caused by power supply? The principle of three-phase cycle power supply is adopted to avoid the three-phase imbalance of the transmission line, and can provide a stable and continuous power supply to the macro base station without affecting the inherent high-voltage transmission line.

[0094] The beneficial effects of the high-voltage transmission line shared tower 1 conductor power supply system of the first embodiment of the present invention are: 1. This power supply method meets the operating power requirements of the macro base station, can not only provide sufficient electric energy to the base station, but also is relatively reliable in terms of safe and stable power supply, and can ensure the normal operation of the base station; 2. The open sharing of "power tower" and "communication tower" is of great benefit to promoting the coordinated development of power and communication infrastructure, especially for the upcoming 5G network deployment, which can be said to kill several birds with one stone; 3. A single-phase transformer 5 is adopted. Compared with the three-phase transformer 5 in the traditional distribution system, this power transformer 5 has higher efficiency and smaller size, and the installation and subsequent operation and maintenance costs are low. The capacity of the transformer 5 can reach 50kW, which meets the power requirements of the macro base station; 4. The principle of three-phase cycle power supply is adopted to avoid the three-phase imbalance of the transmission line, and can provide a stable and continuous power supply to the macro base station without affecting the inherent high-voltage transmission line.

[0095] Embodiment 2 of the power supply system for high-voltage transmission lines sharing the iron tower 1 conductor

[0096] The difference between the second embodiment and the first embodiment lies in the voltage level of the high-voltage transmission line.

[0097] See also Figure 2 and Figure 3 When the voltage level of the transmission line is low at 35kV or below, the fuse 8 is selected, and the specific model is RW5-35kV drop-out fuse 8, which is installed on the 35kV distribution line branch line. Because it has an obvious disconnection point of the high-voltage drop-out fuse 8, it has the function of an isolating switch, creating a safe working environment for the maintenance section line and equipment, and increasing the sense of security of the maintenance personnel. It is installed on the distribution transformer 5 and can be used as the main protection of the distribution transformer 5.

[0098] Embodiment of a method for calculating the hanging height or coverage radius of a high-voltage transmission line sharing tower antenna

[0099] See also Figure 4 A method for calculating the height or coverage radius of an antenna on a shared iron tower for a high-voltage transmission line. The method for calculating the height of an antenna on a shared iron tower for a high-voltage transmission line is applied to a power supply system for a shared iron tower for a high-voltage transmission line. The method for calculating the height or coverage radius of an antenna includes the following steps:

[0100] S1. Determine basic parameters of the base station antenna, where the basic parameters include transmit power, gain, and receive sensitivity.

[0101] S2. Determine the area that the base station antenna needs to cover, so as to determine the values ​​of penetration loss and interference margin;

[0102] S3. Calculate the maximum allowable path loss.

[0103] S4. Determine the antenna coverage radius (the height is known) or antenna height (coverage) through the signal propagation model.

[0104] The radius is known).

[0105] The relationship between the AAU installation height and the macro base station signal coverage range can be calculated through the 5G NR 3.5GHz frequency band link budget and propagation model.

[0106] As an improvement to the calculation method: In S3, the maximum allowable path loss PL in the link budget model calculation is MAX (dB) is calculated using the formula:

[0107] PL MAX =P Tx -L f +G Tx -M f -M l +G Rx -LP -L b -S Rx +ΔL 1 -ΔL 2 (1)

[0108] ΔL 1 =20lgh BS (2)

[0109] ΔL 2 =-1.4d+20.9 (3)

[0110] P Tx is the base station transmit power, and in the uplink it is the base station receive power;

[0111] L f is the feeder loss;

[0112] G Tx is the base station antenna gain;

[0113] M f is the shadow fading and fast fading margin;

[0114] M l is the interference margin;

[0115] G Rx is the mobile phone antenna gain;

[0116] L P is the building penetration loss;

[0117] L b For human body loss;

[0118] S Rx , it is the receiving sensitivity of the mobile phone in downlink, and it is the transmitting power of the mobile phone in uplink;

[0119] d is the average tree distance.

[0120] In view of the location distribution of high-voltage towers, this patent is based on the 5G NR rural macro cellular (Rma-NLOS) propagation model specified in 3GPP.

[0121] In S4, the antenna coverage radius (when the hanging height is known) or the antenna hanging height (when the coverage radius is known) is determined by the signal propagation model, and the calculation method is as follows:

[0122]

[0123]

[0124] Among them: PL Rma-NLOS Take it as the maximum allowable path loss (dB) obtained in formula (1);

[0125] f c is the operating frequency (GHz);

[0126] h BS is the effective height of the base station antenna (m);

[0127] h UT is the effective height of the mobile station antenna (m);

[0128] d 2D is the straight-line distance between the base station antenna and the mobile station antenna (m);

[0129] W is the street width (m);

[0130] h is the average building height (m).

[0131] The beneficial effect of the method for calculating the hanging height or coverage radius of the high-voltage transmission line shared tower antenna of the present invention is: a specific set of equations is given to describe the relationship between the AAU installation height and the signal coverage range. The most suitable AAU installation height can be calculated based on the specific field factors and the required signal coverage range through the set of equations, thereby formulating a reasonable mounting plan to maximize the communication requirements.

[0132] The above is only a specific implementation of the invention, but the protection scope of the invention is not limited thereto. Those skilled in the art should understand that the invention includes but is not limited to the contents described in the drawings and the above specific implementation. Any modification that does not deviate from the functional and structural principles of the invention will be included in the scope of the claims.

Claims

1. A method for calculating the height or coverage radius of a high-voltage transmission line shared tower antenna, characterized in that: The calculation method comprises the following steps: S1. Determine basic parameters of the base station antenna, where the basic parameters include transmit power, gain, and receive sensitivity; S2. Determine the area that the base station antenna needs to cover, so as to determine the values ​​of penetration loss and interference margin; S3. Calculate the maximum allowable path loss. S4. Determine the antenna coverage radius when the hanging height is known or the antenna hanging height when the coverage radius is known through a signal propagation model; In S3, the maximum allowed path loss PL MAX (dB) is calculated using the formula: PL MAX =P Tx -L f +G Tx -M f -M l +G Rx -L P -L b -S Rx +ΔL1-ΔL2 (1) ΔL1=20lgh BS (2) ΔL2=-1.4d+20.9 (3) P Tx is the base station transmit power, and in the uplink it is the base station receive power; L f is the feeder loss; G Tx is the base station antenna gain; M f is the shadow fading and fast fading margin; M l is the interference margin; G Rx is the mobile phone antenna gain; L P is the building penetration loss; L b For human body loss; S Rx , it is the receiving sensitivity of the mobile phone in downlink, and it is the transmitting power of the mobile phone in uplink; d is the average tree spacing; In S4, the antenna coverage radius when the hanging height is known or the antenna hanging height when the coverage radius is known is determined by the signal propagation model, and the calculation method is as follows: Among them: PL Rma-NLOS Take it as the maximum allowable path loss (dB) obtained in formula (1); f c is the operating frequency (GHz); h BS is the effective height of the base station antenna (m); h UT is the effective height of the mobile station antenna (m); d 2D is the straight-line distance between the base station antenna and the mobile station antenna (m); W is the street width (m); h is the average building height (m); The calculation method is applied to a high-voltage transmission line shared iron tower conductor power supply system, the power supply system comprising: A transformer (5), wherein the primary side of the transformer (5) is connected to a transmission line of a high-voltage transmission line, the secondary side of the transformer (5) outputs 220V alternating current, and the casing of the transformer (5) is grounded; A machine room (6), wherein a voltage changing device is provided in the machine room (6); A load device, the load device comprising an active antenna unit (2), the active antenna unit (2) being arranged on an iron tower (1); The secondary side of the transformer (5) is connected to the input end of a voltage variation device, and the output end of the voltage variation device is connected to the active antenna unit (2).

2. The method for calculating the hanging height or coverage radius of a high-voltage transmission line shared tower antenna according to claim 1, characterized in that: The transformer (5) is a single-phase transformer (5); the transformer (5) is mounted on a bracket (9) on the iron tower (1) two meters above the ground.

3. The method for calculating the height or coverage radius of a high-voltage transmission line shared tower antenna according to claim 1, characterized in that: The power extraction system also includes an air conditioner for the machine room (6), and the secondary side of the transformer (5) is connected to the air conditioner for the machine room (6).

4. The method for calculating the hanging height or coverage radius of a high-voltage transmission line shared tower antenna according to claim 1, characterized in that: The primary side of the transformer (5) is connected to two phases of the two sides of the double-circuit iron tower (1).

5. The method for calculating the height or coverage radius of a high-voltage transmission line shared tower antenna according to claim 4, characterized in that: When the adjacent multiple transformers (5) are powered directly, the connection sequence between the primary side and the three-phase line of the iron tower (1) is AB, BC, CA cycle or AB, CA, BC cycle.

6. The method for calculating the hanging height or coverage radius of a high-voltage transmission line shared tower antenna according to claim 1, characterized in that: The voltage variation device comprises a rectifier module, a filter module and a voltage reduction module to output 48V direct current to power the active antenna unit (2).

7. The method for calculating the height or coverage radius of a high-voltage transmission line shared tower antenna according to claim 6, characterized in that: The rectifier module adopts a bridge uncontrolled rectifier circuit, the filter module adopts an LC circuit, and the step-down module adopts a BUCK circuit involving MOSFET.

8. The method for calculating the hanging height or coverage radius of a high-voltage transmission line shared tower antenna according to claim 1, characterized in that: A conductor is led down from the power transmission line and is equipped with a fuse or a circuit breaker according to different voltage levels and then connected to the primary side of a transformer (5); a line is branched from the down conductor and equipped with a lightning arrester (4) and grounded.

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