GB 15707-1995 Limits of radio interference from high voltage AC overhead transmission lines

This standard specifies the radio interference limits of high-voltage AC overhead transmission lines during normal operation. This standard applies to radio interference with a frequency of 0.15 to 30 MHz generated by 110 to 500 kV high-voltage AC overhead transmission lines that have been in operation for more than half a year. GB 15707-1995 Radio Interference Limits of High-voltage AC Overhead Transmission Lines GB15707-1995 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
High Voltage AC Overhead Power Transmission Lines
Limits of radia interfcrencefrom Ac high voltage overhead power transmission lines
Limits of radia interfcrencefrom Ac high voltage overhead power transmission lines 1 Subject Content and Scope of Application
This standard specifies the limits of radio interference from high voltage AC overhead power transmission lines during normal operation GB 15707--1995
This standard applies to radio interference with a frequency of 0.15~30MH2 generated by 110~500kV high voltage AC overhead power transmission lines with an operation time of more than half a year.
2 Reference Standards
GB7349 Methods for measuring radio interference from high voltage overhead power transmission lines and substations GB/T4365 Terminology for electromagnetic compatibility
3 Terminology
In addition to complying with the provisions of GB3/T4365, this standard also adopts the following terms. 3.1 Radio interference limit
The intensity of the light interference field does not exceed the specified value with 80% confidence for 80% of the time. 3.2 Good day
refers to the weather without rain, fog or fog. 4 Radio interference limit
4.1 When the frequency is 0.5MHz, the radio interference limit of high-voltage AC overhead transmission line is as listed in Table 1. Table 1 Radio interference limit (20m away from the projection of the edge conductor)
Wireless
(μV/m)
220-~330
4.2 When the frequency is 1MHz, the radio interference limit of high-voltage AC overhead transmission line is the value in Table 1 minus 5dI3 (μV/n). 4.3 Other frequencies in the frequency band of 0.15°~30MHz. The radio interference limit of high-voltage AC overhead transmission line is revised according to Appendix A. 4.4 The maximum radio interference strength measured at a distance of 20m from the edge conductor shall be measured at 20m. 5 Limit value measurement
5.1 The radio interference field strength obtained according to the method specified in CB7319 shall meet the limit value requirements; it can also be measured only in good weather, and the measured value of the radio interference field strength shall meet the limit value requirements. Approved by the State Administration of Technical Supervision on September 25, 1995 and implemented on October 1, 1996
GB15707-1995
5.2 During measurement, the audio output of the measuring instrument shall be monitored at the same time to ensure that the measurement results are not affected by other strong interference sources such as spark discharge, line carrier, etc. If necessary, measurements shall be made on both sides of the high-voltage AC overhead transmission line. 5.3 When using a rod antenna for measurement, the corona discharge at the end of the rod should be avoided to affect the measurement results. If corona discharge occurs, the measuring antenna should be moved to a place where corona discharge does not occur, or a loop antenna should be used. GB 15707-1995
Appendix A
Frequency correction of radio interference limits
(Supplement)
A1 Frequency correction formula for radio interference limits for high-voltage AC overhead transmission lines The frequency correction of radio interference limits for high-voltage AC overhead transmission lines can be calculated according to the following formula:AE-5[1-2(g10)]
Ah=20lg 0.5+ /1-5
Where: △F—increment of the interference field strength relative to 0.5 MHz in dB (μV/m); f——frequency, MHz.
Note: The applicable frequency range of formula (A1) is 0.15～4 MHz. A2 Application Example
(Al)
When the frequency is 0.8MHz, use formula (A1) to calculate AE as -3dB (μV/m). For 500kV line: at 0.5MHz, the radio interference limit E is 55dB (μV/m), so the radio interference limit at 0.8MHz is E+△E-52dB (μV/m). Appendix
Distance correction of radio interference field strength
(Supplement)
B1 Distance characteristics
The distance characteristics of radio interference of high-voltage overhead power transmission lines are shown in the following formula: 400+(Hh)2
Ex-E+t-Ig
X+(-h)\
Formula: Lx-…-interference field strength at a distance of Xm from the projection of the reverse conductor, dB (V/m); F-…-interference field strength at a distance of 20 from the projection of the side conductor, dB (μV/m), X——distance from the projection of the side conductor, m;
H—height of the side conductor above the ground at the measuring point, m: There is: the installation height of the measuring instrument antenna, m; - attenuation coefficient.
For the 0.15~0.4 MHz range, take 18; for frequencies greater than 0.4 MHz up to 30 MHz, take B as 16.5. Formula (B1) is applicable to the distance from the conductor projection less than 100 m. B2 Distance correction of radio interference field strength
B2.1 According to B.1, the radio interference limit value at a distance of less than 20 m from the edge conductor projection can be calculated. B2.2 According to B.1, the radio interference field strength measured at a distance of less than 20 m from the edge conductor projection can be corrected to 20 m. Ct Basic formula www.bzxz.net
CB 15707--1995
Calculation formula for radio interference field strength of high-voltage AC overhead transmission lines (reference material)
The radio interference field strength of high-voltage AC overhead transmission lines at 5 MHz can be calculated by the following formula. F3.58+12r30+33lg0
Where: E——radio interference field strength, dB(uV/m); gx\maximum potential gradient on the conductor surface kV/eu conductor radius+cm
D-1-the direct distance from the advantage to the conductor. C2 Radio interference field strength of high-voltage AC overhead transmission line (cr)
According to formula ((1), calculate the radio interference field strength generated by each phase of the two-phase conductor of the high-voltage AC overhead transmission line at a certain point. If the radio interference field strength of one phase is at least 3dB (μV/m) greater than that of each of the other phases, then the radio interference field strength value of the high-voltage AC overhead transmission line is the field strength value, otherwise it is calculated according to the following formula. E,+E.
Where: E-radio interference field strength of high-voltage AC overhead transmission line.tlB (μV/rm): F,F The maximum two radio interference field strengths of the three-phase conductors, dB (μV/m). C3 Radio interference field strength value with 80% confidence level for 80% of the time (C2)
The radio interference field strength value of 50% in good weather is calculated by formula (C1). The radio interference field strength value with 80% confidence level for 80% of the time can be increased by 6~10 from this value. dB(μV/m) is obtained. Additional remarks:
This standard is proposed by the Ministry of Electric Power of the People's Republic of China. This standard is under the jurisdiction of the National Radio Interference Standardization Technical Committee C Branch. This standard was drafted by the Wuhan High Voltage Research Institute of the Ministry of Electric Power. The main drafters of this standard are Wu Cao, Li Jianjian, Liang Huidong, Zhang Yingping, and Wu Qishun.
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