Improved method of synchronizing the phase of overhead power lines by electric field induction

Abstract

This invention proposes an improved method for phase matching of synchronous electric field induction overhead lines. The method employs a sensor array-based phase matching mode, specifically: two sensor arrays composed of multiple sensors are installed below the two three-phase overhead lines to be tested. Multiple sensors simultaneously measure the electric field under the overhead lines. The phase of the three-phase overhead lines is determined based on the measured electric field characteristics. Phase matching is then completed by comparing the electric field waveforms of the sensors. Based on the sensor array measurement method, this invention proposes an improved method for measuring the electric field using sensors, which can improve the accuracy of phase matching measurements.

Description

Technical Field

[0001] This invention relates to the field of power grid operation and maintenance technology, and in particular to an improved method for phase verification of synchronous electric field induction overhead lines. Background Technology

[0002] Phase verification refers to checking whether the phase and phase sequence of two power sources or loops are the same using instruments or other means. It is crucial in power system maintenance and operation. Improper handling during phase verification can lead to anything from damaged electrical loads to large-scale power outages; therefore, the reliability of phase verification is paramount for the safe operation of the power system. Depending on the voltage level, phase verification techniques can be divided into two categories: direct phase verification and indirect phase verification. The direct phase verification method involves operators holding a phase verification rod and simultaneously contacting the power lines to be verified. While this method offers high accuracy, it requires contact with high voltage and necessitates four operators simultaneously, making the process cumbersome and affecting reliability. The indirect phase verification method measures voltage on the secondary side, providing a safer operating environment, but it requires cooperation between primary and secondary personnel, also presenting operational challenges.

[0003] In recent years, researchers have proposed non-contact phase measurement methods to address the problems of traditional nuclear phase technology. However, the accuracy of sensor array measurement methods is easily affected by overhead line offset and interference electric fields. Summary of the Invention

[0004] This invention proposes an improved method for phase matching of synchronous electric field induction overhead lines. Based on the sensor array measurement method, it proposes an improved method for measuring the electric field by the sensor, which can improve the accuracy of phase matching measurement.

[0005] The present invention adopts the following technical solution.

[0006] An improved method for phase matching of synchronous electric field induction overhead lines is proposed. The method adopts a phase matching mode based on sensor arrays. Specifically, two sensor arrays consisting of multiple sensors are installed under the two three-phase overhead lines to be tested. Multiple sensors simultaneously measure the electric field under the overhead lines. The phase of the three-phase overhead lines is determined based on the measured electric field characteristics. The phase matching is then completed by comparing the electric field waveforms of the sensors.

[0007] The sensor array is an electric field sensor array, which includes two EF sensors located below two external overhead conductors. The method determines the phase sequence of the three-phase overhead line by calculating the phase angle difference of the sensor array and constructing phase angle characteristic quantities.

[0008] When there is an interference electric field introduced by the overhead line offset, or an interference electric field introduced by other live equipment, the sensor is equipped with an insulating medium to eliminate the interference electric field, so as to maintain a stable phase angle characteristic, thereby improving the accuracy and stability of the phase nucleus.

[0009] The phase arrangement of the three phases ABC of the three-phase overhead line is divided into positive sequence arrangement and negative sequence arrangement. The positive sequence arrangement includes ABC, BCA and CAB, and the negative sequence arrangement includes ACB, CBA and BAC. The electric fields measured at different time points in the positive sequence arrangement and the negative sequence arrangement have the same characteristics. The phase identification method obtains the phase value of the electric field waveform of each sensor by phase identification based on the sensor array, and uses it as a characteristic signal to determine the phase sequence of the three-phase overhead line.

[0010] The nuclear phase method includes phase sequence evaluation and phase evaluation;

[0011] The phase sequence assessment method is as follows: based on the electric field measurement results of two electric field sensors under a three-phase overhead line, the measured phase is used to construct a phase characteristic quantity to determine the positive / negative phase sequence, and then the phase sequence assessment is realized based on the phase characteristic quantity.

[0012] The phase assessment method is as follows: if the electric field waveforms measured by the sensors corresponding to the two overhead lines are the same, based on the consistent phase sequence, it means that the voltage phase of the overhead lines is the same, and the phase verification operation can be completed.

[0013] When two overhead lines are perfectly aligned according to standard installation and there is no offset, the electric field distribution between the lines is uniform. For all positive phase arrangements ABC, BCA, CAB, the phase characteristic is −174.4°, and for all negative phase arrangements ACB, CBA, BAC, the phase characteristic is 174.4°.

[0014] The phase tracing method is a non-contact phase tracing method, specifically as follows: two overhead lines are numbered 123-1'2'3' sequentially; the measurement results of the electric field sensor placed under overhead line 123 are S1 and S2, and the measurement results of the electric field sensor placed under overhead line 1'2'3' are S3 and S4; the electric field phases measured by S1 and S2 are used to calculate the characteristic quantity ΔS using the following formula;

[0015]

[0016] Sensors S1-S4 simultaneously measure the electric field under the overhead line. Based on the electric field characteristics, the phase of the three-phase overhead line is determined, and then the electric field waveform of the sensor is compared to complete the phase detection.

[0017] When two overhead lines are perfectly aligned after standard installation and there is no offset, for all positive phase arrangements ABC, BCA, CAB, ΔS = −174.4°, and for all negative phase arrangements ACB, CBA, BAC, ΔS = 174.4°, phase sequence evaluation is achieved based on ΔS.

[0018] When performing phase assessment, if the waveforms sensed by S1 or S2 of two overhead lines are the same, based on the consistency of phase sequence, it is determined that the voltage phase of the overhead lines is the same, and the phase verification operation is completed.

[0019] To eliminate the effects of overhead line offset and interference electric fields, a solid insulating medium is added to each sensor. D It is used to eliminate the edge effect of the electric field, weaken the influence of stray electric fields, and improve the accuracy of sensor measurements; the dielectric constant of the insulating medium is 9.8.

[0020] Based on the sensor array measurement method, this invention patent proposes a method to improve the electric field measurement of the sensor, which can improve the accuracy of nuclear phase measurement.

[0021] This invention employs a phase-nucleation mode of a sensor array, installing four types of sensors under a three-phase overhead system. By measuring the electric field, it simultaneously measures the distribution of each electric field, and uses an algorithm to analyze the voltage and phase. Furthermore, it improves the accuracy and stability of the phase nucleation through the insulating medium method. Attached Figure Description

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0023] Appendix Figure 1 This is a simulation implementation diagram of the method described in this invention;

[0024] Appendix Figure 2 This is a schematic diagram of the Maxwell finite element simulation model of three non-contact phase measurement methods for overhead lines.

[0025] Appendix Figure 3 This is a schematic diagram showing the normal condition and deviation of a three-phase overhead line;

[0026] Appendix Figure 4 This is a schematic diagram of the electric field simulation results when an overhead line deviates.

[0027] Appendix Figure 5 This is a schematic diagram of a non-contact phase nucleus electric field model that takes into account energized equipment. Detailed Implementation

[0028] As shown in the figure, an improved synchronous electric field induction method for phase detection of overhead lines is proposed. The method adopts a phase detection mode based on sensor arrays. Specifically, two sensor arrays composed of multiple sensors are installed under the two three-phase overhead lines to be tested. Multiple sensors simultaneously measure the electric field under the overhead lines. The phase of the three-phase overhead lines is determined based on the measured electric field characteristics. The phase detection is then completed by comparing the electric field waveforms of the sensors.

[0029] The sensor array is an electric field sensor array, which includes two EF sensors located below two external overhead conductors. The method determines the phase sequence of the three-phase overhead line by calculating the phase angle difference of the sensor array and constructing phase angle characteristic quantities.

[0030] When there is an interference electric field introduced by the overhead line offset, or an interference electric field introduced by other live equipment, the sensor is equipped with an insulating medium to eliminate the interference electric field, so as to maintain a stable phase angle characteristic, thereby improving the accuracy and stability of the phase nucleus.

[0031] The phase arrangement of the three phases ABC of the three-phase overhead line is divided into positive sequence arrangement and negative sequence arrangement. The positive sequence arrangement includes ABC, BCA and CAB, and the negative sequence arrangement includes ACB, CBA and BAC. The electric fields measured at different time points in the positive sequence arrangement and the negative sequence arrangement have the same characteristics. The phase identification method obtains the phase value of the electric field waveform of each sensor by phase identification based on the sensor array, and uses it as a characteristic signal to determine the phase sequence of the three-phase overhead line.

[0032] The nuclear phase method includes phase sequence evaluation and phase evaluation;

[0033] The phase sequence assessment method is as follows: based on the electric field measurement results of two electric field sensors under a three-phase overhead line, the measured phase is used to construct a phase characteristic quantity to determine the positive / negative phase sequence, and then the phase sequence assessment is realized based on the phase characteristic quantity.

[0034] The phase assessment method is as follows: if the electric field waveforms measured by the sensors corresponding to the two overhead lines are the same, based on the consistent phase sequence, it means that the voltage phase of the overhead lines is the same, and the phase verification operation can be completed.

[0035] When two overhead lines are perfectly aligned according to standard installation and there is no offset, the electric field distribution between the lines is uniform. For all positive phase arrangements ABC, BCA, CAB, the phase characteristic is −174.4°, and for all negative phase arrangements ACB, CBA, BAC, the phase characteristic is 174.4°.

[0036] The phase tracing method is a non-contact phase tracing method, specifically as follows: two overhead lines are numbered 123-1'2'3' sequentially; the measurement results of the electric field sensor placed under overhead line 123 are S1 and S2, and the measurement results of the electric field sensor placed under overhead line 1'2'3' are S3 and S4; the electric field phases measured by S1 and S2 are used to calculate the characteristic quantity ΔS using the following formula;

[0037]

[0038] Sensors S1-S4 simultaneously measure the electric field under the overhead line. Based on the electric field characteristics, the phase of the three-phase overhead line is determined, and then the electric field waveform of the sensor is compared to complete the phase detection.

[0039] When two overhead lines are perfectly aligned after standard installation and there is no offset, for all positive phase arrangements ABC, BCA, CAB, ΔS = −174.4°, and for all negative phase arrangements ACB, CBA, BAC, ΔS = 174.4°, phase sequence evaluation is achieved based on ΔS.

[0040] When performing phase assessment, if the waveforms sensed by S1 or S2 of two overhead lines are the same, based on the consistency of phase sequence, it is determined that the voltage phase of the overhead lines is the same, and the phase verification operation is completed.

[0041] To eliminate the effects of overhead line offset and interference electric fields, a solid insulating medium is added to each sensor. D It is used to eliminate the edge effect of the electric field, weaken the influence of stray electric fields, and improve the accuracy of sensor measurements; the dielectric constant of the insulating medium is 9.8.

[0042] Example:

[0043] In this example, the implementation and deployment process of the improved synchronous electric field induction overhead line phase matching method is simulated based on the Maxwell simulation model.

[0044] An improved method for phase comparison of synchronous electric field induction overhead lines, as shown in the appendix. Figure 1 As shown, the two overhead lines are numbered 123-1'2'3' sequentially. Electric field sensors S1 and S2 are placed under overhead line 123, while electric field sensors S3 and S4 are placed under overhead line 1'2'3'. Sensors S1-S4 simultaneously measure the electric field under the overhead lines. Based on the characteristic quantities of the electric field, the phase of the three-phase overhead lines can be determined. Comparing this with the electric field waveforms of the sensors completes phase detection. Furthermore, to eliminate the influence of overhead line offset and interfering electric fields, a solid insulating medium is added to each sensor. D It can eliminate the edge effect of the electric field, weaken the influence of stray electric fields, and improve the accuracy of sensor measurements.

[0045] First, the measurement results of the electric field sensor array under normal operating conditions are simulated, and the phase sequence determination method is explained. Taking overhead line 123 as an example, the finite element electric field simulation model is attached. Figure 2 As shown in Table 1, the phase sequence determination method based on sensor arrays can obtain the phase values ​​of the electric field waveforms of each sensor, which can then be used as characteristic signals to determine the phase sequence of a three-phase overhead line. The simulation model simulates the phase sequence of a three-phase overhead line under positive and negative sequence arrangements, and the results are shown in Table 1. It can be seen that only the electric field phases measured by sensors S1 and S2 are needed to constitute a characteristic quantity ΔS, used to determine the positive / negative phase sequence: for all positive phase sequences (ABC, BCA, CAB), ΔS = −174.4°, while for all negative phase sequences (ACB, CBA, BAC), ΔS = 174.4°. Therefore, phase sequence evaluation can be achieved based on ΔS. Regarding phase evaluation, assuming consistent phase sequence, if the EF waveforms sensed by S1 or S2 of two overhead lines are the same, it means that the voltage phases of the overhead lines are the same, and phase sequence determination can be completed. Therefore, the proposed method can achieve contactless phase sequence determination of overhead lines using only two EF sensors.

[0046]

[0047] According to the appendix Figure 1 It can be seen that an electric field sensor array includes two EF sensors, which are precisely located on two external overhead conductors (such as...). Figure 1 Below conductors #1 and #3 shown. However, in practical applications, the following scenarios may affect the accuracy of the phase nucleus, including: 1) overhead line offset; 2) interference electric field.

[0048] Before phase matching of overhead lines, if the three-phase wires of two overhead lines cannot be perfectly aligned, an uneven electric field will occur because voltage exists on both overhead lines. (Appendix) Figure 3 The diagram illustrates overhead line misalignment, including two completely misaligned overhead lines (Figure b), and instances where a single overhead line is misaligned (Figure 9). Figure 3 (c) where D = 0.8m and L = 5.5m.

[0049] The electric field distribution of the conductors under the above three conditions was simulated using Maxwell simulation. The phase sequence of the two overhead lines is ABC-ABC, as shown in the attached figure. Figure 4 As shown. According to Figure 3 In case (a), under standard overhead line installation, the electric field distribution between the lines is uniform, which ensures the accuracy of the sensor array's electric field measurement. However, compared to the standard case, when two overhead lines are completely misaligned, such as... Figure 3In (b), a significant electric field accumulation phenomenon occurs at the end of the overhead line, and the maximum electric field strength also increases by about 12.2%. When the positions of a certain line in the overhead line are not aligned, as shown in (c), although the maximum electric field strength changes very little compared with the standard case, the electric field strength between the overhead lines increases, and a significant electric field accumulation also occurs at the end of the line.

[0050] When two overhead lines are completely misaligned, the phase measurements obtained by various sensors under different phase sequences were simulated, as shown in Table 2. It can be seen that although the characteristic quantity ΔS still changes, for all positive phase sequences (ABC, BCA, CAB), ΔS = −169.4°~−176.3°, while for all negative phase sequences (ACB, CBA, BAC), ΔS = 169.4°~176.3°. Therefore, when the overhead lines are misaligned during construction, it leads to electric field accumulation in the space above the overhead lines, causing significant fluctuations in the phase angle characteristic quantity ΔS, thus affecting the phase sequence determination results.

[0051]

[0052] In this example, an insulating medium (D) with a dielectric constant between 3 and 10 is placed above the electric field sensor. Taking an insulating medium with a dielectric constant of 9.8 as an example, when two overhead lines are completely misaligned, the sensor array phase measurement results at this point of overhead line misalignment are obtained, as shown in Table 3. Comparing with Table 2, it can be seen that the improved method controls |ΔS| between 174.1° and 174.3°, without affecting the phase sequence determination results.

[0053]

[0054] When performing phase matching on a three-phase overhead line, other electrical devices may be present around the electric field sensor array. The interference electric fields generated by these devices can severely affect the measurement results of the EF sensor. (See attached image) Figure 5 A live device was randomly placed between the overhead line and the sensor array to test the effect of the interference electric field on the non-contact phase measurement method. The results are shown in Table 4. It can be seen that the higher the voltage level of the live device, the greater its impact on the sensor array measurement, and the larger the fluctuation of ΔS.

[0055]

[0056] Under the above conditions, with an insulating medium (dielectric constant of 9.8) added to the sensor array, the phase sequence measurement results are shown in Table 5. Similarly, the improved structure can maintain the stability of ΔS, thereby improving the accuracy and stability of the nucleus phase.

[0057]

Claims

1. An improved method for phase comparison of synchronous electric field induction overhead lines, characterized in that: The method adopts a phase detection mode based on sensor arrays. Specifically, two sensor arrays consisting of multiple sensors are installed under the two three-phase overhead lines to be tested. Multiple sensors simultaneously measure the electric field under the overhead lines. The phase of the three-phase overhead lines is determined based on the measured electric field characteristics. Then, the phase detection is completed by comparing the electric field waveforms of the sensors. The sensor array is an electric field sensor array, which includes two EF sensors located below two overhead conductors. The method determines the phase sequence of a three-phase overhead line by calculating the phase angle difference of the sensor array and constructing phase angle characteristic quantities. The phase arrangement of the three phases ABC of the three-phase overhead line is divided into positive sequence arrangement and negative sequence arrangement. The positive sequence arrangement includes ABC, BCA and CAB, and the negative sequence arrangement includes ACB, CBA and BAC. The electric fields measured at different time points in the positive sequence arrangement and the negative sequence arrangement have the same characteristics. The phase identification method obtains the phase value of the electric field waveform of each sensor by phase identification based on the sensor array, and uses it as a characteristic signal to determine the phase sequence of the three-phase overhead line. The nuclear phase method includes phase sequence evaluation and phase evaluation; The phase sequence assessment method is as follows: based on the electric field measurement results of two electric field sensors under a three-phase overhead line, the measured phase is used to construct a phase characteristic quantity to determine the positive / negative phase sequence, and then the phase sequence assessment is realized based on the phase characteristic quantity. The phase assessment method is as follows: if the electric field waveforms measured by the sensors corresponding to the two overhead lines are the same, based on the consistent phase sequence, it means that the voltage phase of the overhead lines is the same, and the phase verification operation can be completed. The phase tracing method is a non-contact phase tracing method, specifically as follows: two overhead lines are numbered 123-1'2'3' sequentially; the measurement results of the electric field sensor placed under overhead line 123 are S1 and S2, and the measurement results of the electric field sensor placed under overhead line 1'2'3' are S3 and S4; the electric field phases measured by S1 and S2 are used to calculate the characteristic quantity ΔS using the following formula; Sensors S1-S4 simultaneously measure the electric field under the overhead line. Based on the electric field characteristics, the phase of the three-phase overhead line is determined, and then the electric field waveform of the sensor is compared to complete the phase detection. When two overhead lines are perfectly aligned after standard installation and there is no offset, for all positive phase arrangements ABC, BCA, CAB, ΔS = −174.4°, and for all negative phase arrangements ACB, CBA, BAC, ΔS = 174.4°, phase sequence evaluation is achieved based on ΔS. When performing phase assessment, if the waveforms sensed by S1 or S2 of two overhead lines are the same, based on the consistency of phase sequence, it is determined that the voltage phase of the overhead lines is the same, and the phase verification operation is completed.

2. An improved method of synchronizing phase of overhead line circuits by electric field induction as claimed in claim 1 wherein: To eliminate the effects of overhead line offset and interference electric field, a solid insulating medium D is added to each sensor. This medium is used to eliminate the edge effect of the electric field, weaken the influence of stray electric field, and improve the accuracy of sensor measurement. The dielectric constant of the insulating medium is 9.8.

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