Electrical quantity polarity and phase sequence adaptive correction method and system

Abstract

The invention discloses an electrical quantity polarity and phase sequence adaptive correction method and system, and belongs to the technical field of power system relay protection, and the method comprises local voltage and current polarity correction, local voltage and current phase sequence correction, two-side voltage polarity consistency correction, two-side voltage phase sequence consistency correction, and local voltage-current phase sequence correction. The polarity of current on two sides is corrected, and the polarity and phase sequence of voltage and current on two sides of the local and the section are automatically adjusted through a multi-stage dynamic detection and correction process, so that the problem of maloperation or refusal operation of pilot protection and directional protection caused by primary and secondary wiring abnormity in the medium-voltage power distribution network is solved; accuracy and consistency of input data of pilot protection and direction protection algorithms are ensured, and reliability and adaptability of a protection device are remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of relay protection of power systems, and in particular relates to a method and system for adaptively correcting the polarity and phase sequence of electrical quantities. Background Art

[0002] The statements herein merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] In engineering practice, due to installation personnel's misoperation or improper secondary circuit wiring, the voltage and current correspondence on both sides of the line is often mismatched, and the polarity of the transformer is reversed. When new equipment is added to the ring main unit or regular maintenance is carried out, adjustment of the relevant wiring may also cause polarity repetition. Traditional current protection is insensitive to polarity and phase sequence issues, resulting in such anomalies not receiving sufficient attention for a long time. However, statistics show that of the 34 single-phase grounding protection misoperation incidents of integrated ring main units in Xi'an in 2021, 33 were directly attributed to incorrect polarity of the zero-sequence current transformer, which fully confirms the prevalence and severity of such anomalies in the distribution system.

[0004] It is worth noting that the correct operation of most distributed longitudinal protection principles also requires ensuring that the electrical quantities of the same phases on both sides correspond to each other, with consistent polarity and correct phase sequence. To overcome this impact, the current mainstream approach to this problem is to improve management and maintenance capabilities and manually troubleshoot and restore misconnected and reversed lines. However, this approach is inefficient and requires a lot of manpower and material resources. Another solution is to adaptively correct the polarity and phase sequence. However, existing technologies do not consider the situation where both polarity and phase sequence are misconnected, and the application scenario is not targeted at distributed longitudinal protection, so they cannot be directly applied.

[0005] Therefore, an adaptive correction method is urgently needed to realize automatic detection and correction of electrical quantity polarity and phase sequence to ensure the accuracy of the longitudinal protection algorithm. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies in the above-mentioned prior art and to provide a method and system for adaptive correction of the polarity and phase sequence of electrical quantities. Through a multi-level dynamic detection and correction process, the polarity and phase sequence of the voltage and current on both sides of the local and section are automatically adjusted, thereby solving the problem of false operation or refusal of longitudinal protection and directional protection caused by abnormal primary and secondary wiring in the medium-voltage distribution network, ensuring the accuracy and consistency of the input data of the longitudinal protection and directional protection algorithms, and significantly improving the reliability and adaptability of the protection device.

[0007] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0008] On the one hand, the technical solution of the present invention provides a method for adaptive correction of electrical quantity polarity and phase sequence, comprising:

[0009] Calculate the phase difference between the three-phase electrical quantity channels, identify the channels with reverse polarity, and correct the electrical quantities of abnormal channels;

[0010] Detect the phase difference of the three-phase electrical quantity after correction to determine whether it is a reverse phase sequence. If it is a reverse phase sequence, adjust it to the standard positive phase sequence;

[0011] Compare the voltage phase difference of the corresponding channels on both sides of the section to determine whether the polarity on both sides is consistent. If not, correct the voltage phasor on one side;

[0012] Based on the condition that the voltages on both sides are in positive phase sequence, the phase difference between the corresponding channels on both sides is detected. If the phase difference does not meet the preset threshold, the electrical quantity data of one side of the channel is exchanged to achieve phase sequence matching;

[0013] Based on the phase difference range between voltage and current, determine whether the local voltage and current phase sequence are consistent. If not, adjust the phase sequence of the current channel to match the voltage phase sequence.

[0014] Calculate the differential current during normal operation and determine whether the current polarity on both sides is consistent. If the differential current exceeds the limit, reverse the current polarity on one side.

[0015] In at least one embodiment, the electrical quantity includes voltage data or current data.

[0016] In at least one embodiment, the calculating of the phase difference between the channels of the three-phase electrical quantities, identifying the channels with reverse polarity, and correcting the electrical quantities of the abnormal channels specifically includes:

[0017] Matching is performed based on the phase difference between the three-phase electrical quantity channels and the preset polarity reversal combination;

[0018] When the phase difference of a channel deviates from the standard 120° symmetrical distribution by more than the angle margin, the channel is judged to be reverse polarity, and its electrical phase is rotated 180° to restore the 120° symmetrical distribution.

[0019] In at least one embodiment, detecting the phase difference of the three-phase electrical quantities after correction to determine whether it is a reverse phase sequence, and if so, adjusting it to a standard positive phase sequence, specifically includes:

[0020] By detecting that the phase difference between the three-phase channels exceeds the angle margin, it is determined whether the current phase sequence is positive or negative.

[0021] If it is a reverse phase sequence, the electrical quantity data of any two channels are exchanged to adjust to the standard positive phase sequence.

[0022] In at least one embodiment, comparing the voltage phase difference of the corresponding channels on both sides of the segment to determine whether the polarities of the two sides are consistent, and if not, correcting the voltage phasor on one side specifically includes:

[0023] If the voltage phase difference between the corresponding channels on both sides is within a certain deviation range of 0°, 120° or 240°, the polarity is determined to be consistent;

[0024] If the phase difference is within a certain deviation range of 60°, 180°, or 300°, it is determined that the polarity is inconsistent and the phase of the voltage on one side needs to be reversed.

[0025] In at least one embodiment, the phase difference range is set according to the load power factor.

[0026] In at least one embodiment, the method further includes applying the polarity correction and phase sequence mapping relationship determined before the fault to the post-fault data to ensure matching of the polarity and phase sequence of the electrical quantities during the fault.

[0027] In at least one embodiment, the correction mapping relationship is generated using electrical quantity data of at least one cycle before the fault;

[0028] This mapping relationship is applied in real time to the electrical quantity data collected during the fault period to ensure that the correction rules remain effective during the fault period.

[0029] On the other hand, the technical solution of the present invention further provides an electrical quantity polarity and phase sequence adaptive correction system, comprising:

[0030] The local voltage and current polarity correction module is configured to calculate the phase difference between the three-phase electrical quantity channels, identify the channels with reverse polarity, and correct the electrical quantities of the abnormal channels;

[0031] Local voltage and current phase sequence correction: The module is configured to detect the phase difference of the three-phase electrical quantities after correction and determine whether it is a reverse phase sequence. If so, adjust it to a standard positive phase sequence;

[0032] The voltage polarity consistency correction module on both sides is configured to compare the voltage phase difference of the corresponding channels on both sides of the section to determine whether the polarity of the two sides is consistent. If not, the voltage phase of one side is corrected;

[0033] The voltage phase sequence consistency correction module on both sides is configured to: based on the condition that the voltages on both sides are in positive phase sequence, detect the phase difference between the corresponding channels on both sides. If the phase difference does not meet the preset threshold, the electrical quantity data of one side's channel is exchanged to achieve phase sequence matching;

[0034] The local voltage-current phase sequence correction module is configured to: determine whether the local voltage and current phase sequences are consistent based on the phase difference range between the voltage and current; if not, adjust the phase sequence of the current channel to match the voltage phase sequence;

[0035] The current polarity correction module on both sides is configured to: calculate the difference current size during normal operation, determine whether the polarity of the current on both sides is consistent, and reverse the polarity of the current on one side if the difference current exceeds the limit.

[0036] In at least one embodiment, it further includes: a fault electrical quantity correction module, configured to: apply the polarity correction and phase sequence mapping relationship determined before the fault to the post-fault data to ensure the matching of the electrical quantity polarity and phase sequence during the fault.

[0037] The beneficial effects of the technical solution of the present invention are as follows:

[0038] 1) The present invention provides an adaptive correction method for the polarity and phase sequence of electrical quantities. Through a multi-stage dynamic detection and correction process, the polarity and phase sequence of the voltage and current on both sides of the local and section are automatically adjusted. This solves the problem of malfunction or refusal of longitudinal protection and directional protection caused by abnormal primary and secondary wiring in medium-voltage distribution networks, ensures the accuracy and consistency of the input data of the longitudinal protection and directional protection algorithms, and significantly improves the reliability and adaptability of the protection device.

[0039] 2) The method for adaptive correction of electrical quantity polarity and phase sequence of the present invention performs adaptive correction on the collected data without the need to check and adjust the primary and secondary wiring, thereby reducing the workload and cost of manual troubleshooting and greatly improving work efficiency.

[0040] 3) The method for adaptively correcting the polarity and phase sequence of electrical quantities of the present invention can ensure the correct operation of protection under normal or abnormal wiring conditions, thereby improving the reliability of longitudinal protection and directional protection devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0042] Figure 1 This is a schematic diagram of the steps of a method for adaptively correcting the polarity and phase sequence of electrical quantities according to the present invention;

[0043] Figure 2 This is a schematic diagram of a simple distribution network in Example 1 of the present invention;

[0044] Figure 3 This is an overall flow chart of the method for adaptively correcting the polarity and phase sequence of electrical quantities in Example 1 of the present invention;

[0045] Figure 4 Schematic diagram of the distribution network simulation model in Example 1 of the present invention;

[0046] Figure 5 1 is a schematic diagram of the simulation results of Case 1 in Example 1 of the present invention;

[0047] Figure 6 1 is a schematic diagram of the simulation results of Case 2 in Example 1 of the present invention;

[0048] Figure 7 Schematic diagram of the simulation results of Case 3 in Example 1 of the present invention. DETAILED DESCRIPTION

[0049] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0050] As introduced in the background technology, the purpose of the present invention is to overcome the shortcomings of the above-mentioned existing technologies and provide a method and system for adaptive correction of electrical quantity polarity and phase sequence. Through a multi-level dynamic detection and correction process, the polarity and phase sequence of the voltage and current on both sides of the local and section are automatically adjusted, which solves the problem of false operation or refusal of longitudinal protection and directional protection caused by abnormal primary and secondary wiring in the medium-voltage distribution network, ensures the accuracy and consistency of the input data of the longitudinal protection and directional protection algorithms, and significantly improves the reliability and adaptability of the protection device.

[0051] Example 1

[0052] In a typical embodiment of the present invention, Figure 1 As shown, this embodiment discloses a method for adaptively correcting the polarity and phase sequence of electrical quantities, comprising the following steps:

[0053] Step 1. Local voltage and current polarity correction: Calculate the phase difference between the three-phase electrical quantity channels, identify the channels with reverse polarity, and correct the electrical quantities of the abnormal channels;

[0054] Step 2. Local voltage and current phase sequence correction: Detect the phase difference of the three-phase electrical quantities after correction to determine whether it is a reverse phase sequence. If it is a reverse phase sequence, adjust it to the standard positive phase sequence;

[0055] Step 3. Correct the voltage polarity consistency on both sides: Compare the voltage phase difference of the corresponding channels on both sides of the section to determine whether the polarity on both sides is consistent. If not, correct the voltage phasor on one side;

[0056] Step 4. Phase sequence consistency correction for voltages on both sides: Based on the condition that the voltages on both sides are in positive phase sequence, the phase difference between the corresponding channels on both sides is detected. If the phase difference does not meet the preset threshold, the electrical quantity data of one channel on one side is swapped to achieve phase sequence matching.

[0057] Step 5. Local voltage-current phase sequence correction: Based on the phase difference range between voltage and current, determine whether the local voltage and current phase sequences are consistent. If not, adjust the phase sequence of the current channel to match the voltage phase sequence.

[0058] Step 6. Correct the polarity of the current on both sides: Calculate the differential current during normal operation and determine whether the polarity of the current on both sides is consistent. If the differential current exceeds the limit, reverse the polarity of the current on one side.

[0059] The above-mentioned method for adaptive correction of electrical quantity polarity and phase sequence is described in detail below in conjunction with specific implementation methods.

[0060] Reference Figure 2 In the simple distribution network shown, if the polarity or phase sequence of electrical quantities is incorrectly connected, the electrical quantities connected to the three-phase ABC terminals of the protection device's voltage or current may not be the actual electrical quantities of that phase. For ease of description, in this embodiment, the three-phase ABC terminals are assumed to be channel 1, channel 2, and channel 3, respectively. The following steps 1 through 6 ensure that the voltage and current polarity on both sides are consistent and the phase sequence is consistent.

[0061] Step 1. Correct the polarity of local voltage and current.

[0062] The goal of step 1 is to achieve consistent polarity of local electrical quantities. Under normal operating conditions, when the polarity of the three-phase voltage / current phases is consistent, the three phases are symmetrically distributed at 120°; if the polarity of any phase is reversed, the phase will be 300° away from the adjacent phase. Table 1 lists the phase characteristics of all 24 wiring combinations. In the table, ABC means that channel 1 is phase A, channel 2 is phase B, and channel 3 is phase C. The other phase sequences are similar. is the phase difference between the two channels, and the subscripts 1, 2, and 3 represent the voltage or current channels 1-3 of the protection device, respectively.

[0063] Table 1 All results in the case of local polarity reversal

[0064]

[0065] As shown in Table 1, by calculating the phase difference between the electrical quantities of each channel, the channel with abnormal polarity can be identified. Further, the goal of step 1 can be achieved by simply rotating the phasor of the electrical quantity of the channel by 180°, that is, achieving consistent polarity of the local electrical quantity.

[0066] Taking into account the influence of factors such as system imbalance and calculation error, the polarity detection criterion is shown in formula (1):

[0067]

[0068] in, The angle margin for detecting the polarity of local electrical quantities must cover the calculation error. In this embodiment, 30° is used. The correction results for Cases 1-4 are shown in Table 2.

[0069] Table 2 Local electrical quantity polarity correction method

[0070]

[0071] Step 2. Correct the local voltage and current phase sequence.

[0072] The goal of step 2 is to achieve a positive phase sequence for the local electrical quantities. After step 1, the polarity of the three-phase electrical quantities is consistent, and on this basis, the phase sequence is detected and corrected. When the phase sequence is correct, channel 1 leads channel 2 by 120°, channel 2 leads channel 3 by 120°, and channel 3 leads channel 1 by 120°. When the phase sequence is incorrect, channel 1 leads channel 3 by 120°, channel 3 leads channel 2 by 120°, and channel 2 leads channel 1 by 120°. Table 3 shows all six phase sequence arrangements:

[0073] Table 3 All possible results of the phase sequence of local electrical quantities

[0074]

[0075] It is easy to see from Table 3 that by detecting the phase difference of the three channels, it is possible to determine whether the phase sequence is correct. Considering the influence of factors such as calculation error, the phase sequence detection criterion is as follows:

[0076]

[0077] Among them, Case 1 is the positive phase sequence, and Case 2 is the negative phase sequence. The angle margin for local phase sequence detection must cover calculation errors. In this embodiment, 30° is used. If the phase sequence is detected to be reversed, the electrical quantities of two channels can be swapped. Table 4 shows the phase sequence correction method.

[0078] Table 4 Local electrical quantity phase sequence correction method

[0079]

[0080]

[0081] Step 3. Correct the voltage polarity consistency on both sides.

[0082] The goal of step 3 is to achieve voltage polarity consistency on both sides. Steps 1 and 2 achieve local electrical quantity polarity consistency and correct the phase sequence to a positive phase sequence. However, the polarity and phase sequence of the electrical quantities on both sides of the section may not be consistent, and the polarity and phase sequence of the electrical quantities on both sides of the section must be unified. Due to the short distribution lines and low loads, the phases of the voltages on both sides are almost identical when the polarity is consistent. Based on this, the voltage phase difference of the corresponding channels on both sides, when both sides have a positive phase sequence, is shown in Table 5. The data in the table is calculated under ideal conditions, assuming that the phases of the voltages on both sides are the same when the polarity is consistent and opposite when the polarity is inconsistent.

[0083] Table 5 All possible results of voltage polarity wiring on both sides

[0084]

[0085] As can be seen from Table 5, when the polarity on both sides is consistent, the voltage phase difference of the corresponding channels on both sides may be 0°, 120°, or 240°; when the polarity on both sides is inconsistent, the voltage phase difference of the corresponding channels on both sides may be 60°, 180°, or 300°. The voltage polarity detection criterion on both sides is as follows:

[0086]

[0087] in, The phase difference between the two channels with the same voltage, The angle margin for detecting the voltage polarity on both sides must cover the calculation error. In this embodiment, 30° is used. The correction results corresponding to Case 1-2 are shown in Table 6.

[0088] Table 6 Correction method for inconsistent voltage polarity on both sides

[0089]

[0090] Step 4. Correct the voltage phase sequence consistency on both sides.

[0091] The goal of step 4 is to achieve a consistent voltage phase sequence on both sides. After steps 1-3, the voltage polarity on both sides is consistent, and the phase sequence is positive. However, since there are three possible positive phase sequences, it is also necessary to ensure that the channels on both sides are in the same phase. Table 5-9 lists all nine possible positive phase sequence combinations on both sides.

[0092] Table 7 All results of positive phase sequence combination of voltage on both sides

[0093]

[0094]

[0095] Combined with Table 7, the criterion for detecting the consistency of the voltage phase sequence on both sides is shown in formula (4):

[0096]

[0097] in, The angle margin for detecting the voltage phase sequence on both sides must cover the calculation error. In this embodiment, 30° is used. The corresponding correction results for Cases 1-3 are shown in Table 8.

[0098] Table 8 Voltage phase sequence consistency correction method on both sides

[0099]

[0100] Step 5. Local voltage-current phase sequence correction.

[0101] The goal of step 5 is to achieve consistent local voltage and current phase sequences. Steps 1-5 ensure consistent voltage polarity and phase sequence on both sides, and consistent local three-phase current polarity and positive phase sequence. Based on the consistency of the voltage phase sequence on both sides, the precise correspondence of the local voltage and current phase sequences directly ensures automatic matching of the current phase sequences on both sides.

[0102] For medium-voltage distribution network loads with a power factor (≥0.95), the permissible voltage-current phase difference range is (0°, 19°) ∪ (349°, 360°) ∪ (161°, 199°). This reflects the phase relationship boundary between voltage and current under capacitive and inductive load conditions and provides a theoretical basis for phase sequence determination. Table 9 lists all nine cases with different positive voltage and current phase sequences.

[0103] Table 9 All results of local voltage and current phase sequence combinations

[0104]

[0105] Based on Table 9, the local voltage-current phase sequence detection criterion is shown in formula (5):

[0106]

[0107] in, The angle margin for local voltage-current phase sequence detection must cover calculation errors. In this embodiment, 30° is used. If Case 1 is satisfied, the voltage and current phase sequences correspond and no correction is required. If Cases 2 and 3 are satisfied, the voltage and current phase sequences do not correspond and the phasors collected by the current channel must be swapped. Table 10 shows the current phasor correction method.

[0108] Table 10 Local current phase sequence correction method

[0109]

[0110] Step 6. Correct the polarity of the current on both sides.

[0111] The goal of step 6 is to achieve the consistency of the polarity of the current on both sides. The above steps 1-5 achieve the corresponding phase sequence of the current on both sides, and further, it is necessary to achieve the consistency of the polarity of the current on both sides. When the polarity of the current on both sides is consistent, the calculated differential current during normal operation is zero (if the protected section contains a T-connected branch, the differential current is the sum of the currents on the T-connected branch line. Under normal circumstances, the load of the T-connected form is small and will not cause the direction of the current on both sides to change). When the polarity of the current on both sides is opposite, the calculated differential current during normal operation is larger. Therefore, the magnitude of the differential current can be used to determine whether the polarity of the current on both sides is consistent. The judgment criterion is shown in formula (6):

[0112] |I M-φ +I N-φ |≥K rel max{|I M-φ |,|I N-φ |} (6);

[0113] Based on criterion (6), if the criterion is not satisfied, the polarities of the currents on both sides are consistent; if the criterion is satisfied, the polarities of the currents on both sides are inconsistent, and the polarity of the currents on both sides can be made consistent by correcting the polarity of the current on one side.

[0114] The above steps utilize data from normal system operation to ensure consistent voltage and current polarity and corresponding phase sequence on both sides. When a fault occurs and protection is activated, the protection device can store data from several cycles prior to the fault. This pre-fault data can then be used to determine and correct the voltage and current polarity and phase sequence on both sides.

[0115] As an optional implementation, the two steps of local voltage-current phase sequence correction and current polarity correction on both sides in steps 5 and 6 can also be replaced by current polarity consistency correction on both sides and current phase sequence consistency correction on both sides, which can also achieve the goals of steps 5 and 6 and is also within the protection scope of the present invention.

[0116] Step 7: Correction of fault electrical quantities.

[0117] The goal of step 7 is to achieve polarity and phase sequence correction of the fault electrical quantities, that is, to achieve polarity and phase sequence correction of the fault voltage and current. Based on the correction rules established in steps 1-6, the polarity correction and phase sequence mapping relationship determined before the fault is extended to the electrical quantities after the fault, further achieving matching of the voltage and current polarity and phase sequence after the fault on both sides. As a further implementation method, the correction mapping relationship is generated using electrical quantity data of at least one cycle before the fault; this mapping relationship is applied in real time to the electrical quantity data collected during the fault period to ensure that the correction rules remain in effect during the fault period.

[0118] After the above steps, the overall electrical quantity calibration process is shown in Figure 3Furthermore, an active distribution network model was constructed using RSCAD, and RTDS was used to simulate and verify the electrical quantity polarity and phase sequence correction method proposed in this embodiment:

[0119] (1) Model building

[0120] like Figure 4 As shown in the figure, the distribution network voltage level is 10kV, the system power supply is 110kV, the main transformer is 110 / 10.5kV, the main transformer equivalent impedance is 0.22jΩ, the lengths of sections B1B2, B2B3, and B3B4 are 1, 3, and 2km respectively, and the line unit impedance is 0.125+0.095jΩ / km. Fault points F1, F2, and F3 are located one kilometer away from busbars B2, B3, and B4 respectively. T Located 2 km away from busbar B3, the capacity of Load1-load3 is 2MVA, load T The default capacity is 1 MVA, and the power factor for all loads is 0.95. The IBDG adopts a negative-sequence current suppression control strategy and has a capacity of 1 MW. CB1-CB6 are circuit breakers. Two intelligent terminal prototypes, STU1 and STU2, with QDP functionality, were developed and located on either side of section B2B3, controlling circuit breakers CB3 and CB4, respectively. These prototypes can collect voltage and current information at CB3 and CB4, determine the fault location, and control the opening and closing of each switch. In this simulation, section B2B3 is the target section, with F1 and F3 representing out-of-zone faults and F2 representing an in-zone fault.

[0121] (2) Simulation analysis

[0122] Set up the following failure cases:

[0123] Case 1: At F2, ABC passes through a 0.5Ω transition resistor to artificially change the analog input of the protection prototype STU1, so that the polarity of its A phase voltage is reversed, simulating the wiring errors that may occur during on-site construction.

[0124] Case 2: At F2, AB passes through a 10Ω transition resistor, and the analog input of the protection prototype STU1 is artificially changed, so that the polarity of the A phase voltage is reversed and the phase sequence of the BC phase current is wrong, simulating the wiring errors that may occur during on-site construction.

[0125] Case 3: At F1, ABC is connected through a 0.5Ω transition resistor, and the AI ​​terminal block of the protection prototype is connected incorrectly, causing the polarity of the B phase voltage of STU1 to be reversed and the phase sequence of the BC phase voltage of STU2 to be incorrect, simulating the wiring errors that may occur on both sides during on-site construction.

[0126] Figure 5This is the background detection result for reverse polarity of the phase A voltage on the STU1 side when an ABC fault occurs at F2. The initial three-phase voltage acquisition results before the local fault are: 59.3∠45° (reverse polarity), 59.2∠106°, and 59.4∠346°, which are consistent with the actual acquisition results of the prototype. After correction by the prototype, the three-phase voltages are: 59.3∠225°, 59.2∠106°, and 59.4∠346°. The phase correction of the phase A voltage is correct. Similarly, the voltage after the fault is also corrected correctly. Figure 6 This is the background detection result of STU1 when the A phase voltage polarity is reversed and the BC phase current phase sequence is wrong when an AB through 10Ω fault occurs at F2. It can be seen that after correction, the phase sequence polarity of the three-phase voltage and current all meet the characteristics of the AB phase fault, verifying the effectiveness of the proposed scheme.

[0127] Figure 7 This is a background print of the reverse polarity of the B-phase voltage of STU1 and the wrong phase sequence of the BC-phase voltage of STU2 when an ABC-through-0.5Ω fault occurs at F1. In the figure, the B-phase voltage on the STU1 side is correctly corrected, and the phase sequence of the BC-phase voltage on the STU2 side is also correctly corrected, verifying the effectiveness of the proposed method.

[0128] The above simulation results show that the protection prototype can correctly identify faults inside and outside the zone under conditions of single-sided and double-sided wiring abnormalities, and is not affected by the superposition of multiple wiring abnormalities. This verifies the fault tolerance of the adaptive correction algorithm to complex wiring abnormalities.

[0129] In addition, the data synchronization of the method for adaptive correction of electrical quantity polarity and phase sequence in this embodiment can be achieved by using IRIG-B code synchronization technology, GPS / Beidou satellite synchronization technology, or fault moment self-synchronization technology.

[0130] Example 2

[0131] In a typical embodiment of the present invention, this embodiment discloses an electrical quantity polarity and phase sequence adaptive correction system, including:

[0132] The local voltage and current polarity correction module is configured to calculate the phase difference between the three-phase electrical quantity channels, identify the channels with reverse polarity, and correct the electrical quantities of the abnormal channels;

[0133] Local voltage and current phase sequence correction: The module is configured to detect the phase difference of the three-phase electrical quantities after correction and determine whether it is a reverse phase sequence. If so, adjust it to a standard positive phase sequence;

[0134] The voltage polarity consistency correction module on both sides is configured to compare the voltage phase difference of the corresponding channels on both sides of the section to determine whether the polarity of the two sides is consistent. If not, the voltage phase of one side is corrected;

[0135] The voltage phase sequence consistency correction module on both sides is configured to: based on the condition that the voltages on both sides are in positive phase sequence, detect the phase difference between the corresponding channels on both sides. If the phase difference does not meet the preset threshold, the electrical quantity data of one side's channel is exchanged to achieve phase sequence matching;

[0136] The local voltage-current phase sequence correction module is configured to: determine whether the local voltage and current phase sequences are consistent based on the phase difference range between the voltage and current; if not, adjust the phase sequence of the current channel to match the voltage phase sequence;

[0137] The current polarity correction module on both sides is configured to: calculate the difference current size during normal operation, determine whether the polarity of the current on both sides is consistent, and reverse the polarity of the current on one side if the difference current exceeds the limit.

[0138] It also includes: a fault electrical quantity correction module, which is configured to: apply the polarity correction and phase sequence mapping relationship determined before the fault to the post-fault data to ensure the matching of the electrical quantity polarity and phase sequence during the fault.

[0139] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for adaptively correcting the polarity and phase sequence of electrical quantities, characterized in that: include: Calculate the phase difference between the three-phase electrical quantity channels, identify the channels with reverse polarity, and correct the electrical quantities of abnormal channels; Detect the phase difference of the three-phase electrical quantity after correction to determine whether it is a reverse phase sequence. If it is a reverse phase sequence, adjust it to the standard positive phase sequence; Compare the voltage phase difference of the corresponding channels on both sides of the section to determine whether the polarity on both sides is consistent. If not, correct the voltage phasor on one side; Based on the condition that the voltages on both sides are in positive phase sequence, the phase difference between the corresponding channels on both sides is detected. If the phase difference does not meet the preset threshold, the electrical quantity data of one side of the channel is exchanged to achieve phase sequence matching; Based on the phase difference range between voltage and current, determine whether the local voltage and current phase sequence are consistent. If not, adjust the phase sequence of the current channel to match the voltage phase sequence. Calculate the differential current during normal operation and determine whether the current polarity on both sides is consistent. If the differential current exceeds the limit, reverse the current polarity on one side.

2. The method for adaptively correcting the polarity and phase sequence of electrical quantities according to claim 1, wherein: The electrical quantity includes voltage data or current data.

3. The method for adaptively correcting the polarity and phase sequence of electrical quantities according to claim 1, wherein: The calculating of the phase difference between the channels of the three-phase electrical quantities, identifying the channels with reverse polarity, and correcting the electrical quantities of the abnormal channels specifically includes: Matching is performed based on the phase difference between the three-phase electrical quantity channels and the preset polarity reversal combination; When the phase difference of a channel deviates from the standard 120° symmetrical distribution by more than the angle margin, the channel is judged to be reverse polarity, and its electrical phase is rotated 180° to restore the 120° symmetrical distribution.

4. The method for adaptively correcting the polarity and phase sequence of electrical quantities according to claim 1, wherein: The detection of the phase difference of the three-phase electrical quantities after correction to determine whether it is a reverse phase sequence, and if it is a reverse phase sequence, adjusting it to a standard positive phase sequence, specifically includes: By detecting that the phase difference between the three-phase channels exceeds the angle margin, it is determined whether the current phase sequence is positive or negative. If it is a reverse phase sequence, the electrical quantity data of any two channels are exchanged to adjust to the standard positive phase sequence.

5. The method for adaptively correcting the polarity and phase sequence of electrical quantities according to claim 1, wherein: The voltage phase difference of the corresponding channels on both sides of the comparison section is judged to determine whether the polarities of the two sides are consistent. If not, the voltage phasor on one side is corrected, specifically including: If the voltage phase difference between the corresponding channels on both sides is within a certain deviation range of 0°, 120° or 240°, the polarity is determined to be consistent; If the phase difference is within a certain deviation range of 60°, 180°, or 300°, it is determined that the polarity is inconsistent and the phase of the voltage on one side needs to be reversed.

6. The method for adaptively correcting the polarity and phase sequence of electrical quantities according to claim 1, wherein: The phase difference range is set according to the load power factor.

7. The method for adaptively correcting the polarity and phase sequence of electrical quantities according to claim 1, wherein: Also includes: The polarity correction and phase sequence mapping relationship determined before the fault is applied to the post-fault data to ensure the matching of the polarity and phase sequence of the electrical quantities during the fault.

8. The method for adaptively correcting the polarity and phase sequence of electrical quantities according to claim 7, wherein: Generate a correction mapping relationship using electrical quantity data of at least one cycle before the fault; This mapping relationship is applied in real time to the electrical quantity data collected during the fault period to ensure that the correction rules remain effective during the fault period.

9. An electrical quantity polarity and phase sequence adaptive correction system, characterized in that: include: The local voltage and current polarity correction module is configured to calculate the phase difference between the three-phase electrical quantity channels, identify the channels with reverse polarity, and correct the electrical quantities of the abnormal channels; Local voltage and current phase sequence correction: The module is configured to detect the phase difference of the three-phase electrical quantities after correction and determine whether it is a reverse phase sequence. If so, adjust it to a standard positive phase sequence; The voltage polarity consistency correction module on both sides is configured to compare the voltage phase difference of the corresponding channels on both sides of the section to determine whether the polarity of the two sides is consistent. If not, the voltage phase of one side is corrected; The voltage phase sequence consistency correction module on both sides is configured to: based on the condition that the voltages on both sides are in positive phase sequence, detect the phase difference between the corresponding channels on both sides. If the phase difference does not meet the preset threshold, the electrical quantity data of one side's channel is exchanged to achieve phase sequence matching; The local voltage-current phase sequence correction module is configured to: determine whether the local voltage and current phase sequences are consistent based on the phase difference range between the voltage and current; if not, adjust the phase sequence of the current channel to match the voltage phase sequence; The current polarity correction module on both sides is configured to calculate the difference in current during normal operation, determine whether the polarity of the current on both sides is consistent, and reverse the polarity of the current on one side if the difference in current exceeds the limit.

10. The electrical quantity polarity and phase sequence adaptive correction system according to claim 9, characterized in that: Also includes: The fault electrical quantity correction module is configured to apply the polarity correction and phase sequence mapping relationship determined before the fault to the post-fault data to ensure the matching of the electrical quantity polarity and phase sequence during the fault period.

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