Method for checking current phase and phase sequence of line measurement terminal by adopting load power factor angle

Abstract

The invention discloses a method for checking a current phase sequence of a line measurement terminal by adopting a load power factor angle, which is applied to a 10kV system which is an ungrounded system, an arc suppression coil grounded system and a small resistance grounded system. The method comprises the following steps of: acquiring three-phase voltage of a 10kV bus of a transformer substation, active power P and reactive power Q of a 10kV line interval and three-phase current of a power distribution measurement terminal at the head end of the 10kV line, and respectively calculating a power factor angle of the 10kV line interval of the transformer substation and a phase angle of each phase current of the power distribution measurement terminal at the head end of the 10kV line lagging behind each phase voltage of the 10kV bus of the transformer substation in real time; and according to the condition of the difference value of the two angles, the phase sequence of each phase of current of each measuring terminal on the 10kV distribution line is automatically checked, so that corresponding relay protection is carried out. The method is accurate in judgment, the implementation scheme is simple and easy to implement, and the power supply reliability of the 10kV power distribution network can be improved.

Description

Technical Field

[0001] The present invention relates to a method for verifying the current phase and phase sequence of a line measurement terminal by using the load power factor angle, and belongs to the technical field of protection and control of power distribution networks. Background Art

[0002] In an ungrounded system, an arc suppression coil grounded system, and a small resistance grounded system, measurement terminals (SGS for overhead type and RCMU for cable type) are generally installed at each measurement point on a 10 kV distribution line to serve as measurement terminals for detecting the current in a certain line segment during a single-phase ground or interphase short circuit fault. After the above measurement terminals are installed, it is necessary to check the three-phase current phase and phase sequence to ensure that the phase and phase sequence of each phase current of A, B, and C of each measurement terminal on the distribution line are similar to and consistent with the three-phase current phase of the 10 kV line interval of the substation (simply referred to as the correct phase and phase sequence of each phase current of the line), so as to ensure the correct operation of each measurement terminal. For the check of the three-phase current phase and phase sequence, it is generally verified by experience at present: that is, by observing whether the phase of each phase current of each line measurement terminal on the 10 kV bus of the substation is similar. This approach often leads to incorrect judgments. For example, when there is local power generation or new energy generation on the line, there will be a situation where active power and reactive power are fed back to the power grid, and the above conclusion will not hold and the judgment will be incorrect. Summary of the Invention

[0003] The purpose of the present invention is to propose a technical solution for an ungrounded system, an arc suppression coil grounded system, and a small resistance grounded system in a 10 kV system. Based on wide-area synchronous information, it collects the three-phase voltage of the 10 kV bus of the substation, the active power P and reactive power Q of the 10 kV line interval, and the three-phase current of the distribution measurement terminal at the head end of the 10 kV line. It respectively calculates the power factor angle of the 10 kV line interval of the substation and the phase angle by which each phase current of the distribution measurement terminal at the head end of the 10 kV line lags behind each phase voltage of the 10 kV bus of the substation in real time. According to the situation of the difference between these two angles, it automatically checks the phase and phase sequence of each phase current of each measurement terminal on the 10 kV distribution line, so as to perform corresponding relay protection.

[0004] The purpose of the present invention is achieved through the following technical solutions:

[0005] A method for verifying the current phase and phase sequence of a line measurement terminal by using the load power factor angle includes the following steps:

[0006] Step 1:

[0007] ⑴ Collect the three-phase voltage of the 10 kV bus of the substation, the active power P and reactive power Q of each 10 kV line interval in real time, and calculate the power factor angle of the 10 kV line interval of the substation in real time

[0008] ⑵Collect the three-phase currents of the distribution measurement terminal at the head end of the 10 kV line at the same moment as ⑴, and take the three-phase voltages of the 10 kV busbar of the substation as the reference to calculate the phase angle by which the phase current of the distribution measurement terminal at the head end of the 10 kV line of the substation lags behind the phase voltage of the 10 kV busbar of the substation in real time.

[0009] ⑶Calculate the phase current phase angle of the distribution measurement terminal at the head end of the 10 kV line and the power factor angle of the 10 kV line interval of the substation the difference between these two angles Judge whether it meets the qualified standard:

[0010] ①When it meets the qualified standard, it means that the phase sequence of each phase current of the distribution measurement terminal at the head end of the 10 kV line is correct;

[0011] ②When it does not meet the qualified standard, it means that an error has occurred, and the phase sequence of each phase current of this distribution measurement terminal needs to be adjusted and corrected. The adjustment and correction method is as follows:

[0012] When taking the phase voltage of phase A of the 10 kV busbar of the substation as the reference, take the difference The phase with the smallest difference is marked as phase A, and then the phase currents of the other two phases are adjusted and marked as phase B and phase C in sequence according to the requirements of the positive phase sequence;

[0013] When taking the phase voltage of phase B of the 10 kV busbar of the substation as the reference, take the difference The phase with the smallest difference is marked as phase B, and then the phase currents of the other two phases are adjusted and marked as phase C and phase A in sequence according to the requirements of the positive phase sequence;

[0014] When taking the phase voltage of phase C of the 10 kV busbar of the substation as the reference, take the difference The phase with the smallest difference is marked as phase C, and then the phase currents of the other two phases are adjusted and marked as phase A and phase B in sequence according to the requirements of the positive phase sequence;

[0015] Step 2, on the basis of confirming the phase sequence of the three-phase currents of the head-end distribution measurement terminal, further verify other sampling points, that is, the phase sequence of the three-phase currents of each distribution measurement terminal downstream of the head-end distribution measurement terminal; the verification is carried out at the time point with the smallest load fluctuation, avoiding the power generation period of local power plants on the line, reducing the verification error and preventing misjudgment.

[0016] The method is as follows:

[0017] (1) Collect the three-phase voltages of the 10kV bus of the substation and the three-phase currents of each distribution measurement terminal downstream of the distribution measurement terminal at the head of this line. Taking the phase voltage of the 10kV bus of the substation as the reference, calculate in real time the phase angle by which the phase current of each distribution measurement terminal on the 10kV line of the substation lags behind the phase voltage of the 10kV bus of the substation.

[0018] (2) Collect the phase currents of the distribution measurement terminals at other sampling points on the 10kV line, and calculate in real time the phase angle by which the three-phase current of this distribution measurement terminal lags behind the phase voltage of the 10kV bus of the substation. Compare with the phase angle of the distribution measurement terminal at the head of this line Calculate the difference Judge whether it meets the qualified standard;

[0019] ① If it meets the qualified standard, it means that the phase and phase sequence of each phase current of the distribution measurement terminal downstream of the head of the 10kV line are correct;

[0020] ② If it does not meet the qualified standard, it is necessary to adjust and correct the phase and phase sequence of each phase current of this distribution measurement terminal;

[0021] The method of adjustment and correction is as follows:

[0022] When taking the phase voltage of phase A of the 10kV bus of the substation as the reference, take the difference The phase with the smallest difference is marked as phase A, and then the phase angles of the other two-phase currents are adjusted and marked as phase B and phase C in sequence according to the requirements of the positive phase sequence;

[0023] When taking the phase voltage of phase B of the 10kV bus of the substation as the reference, take the difference The phase with the smallest difference is marked as phase B, and then the phase angles of the other two-phase currents are adjusted and marked as phase C and phase A in sequence according to the requirements of the positive phase sequence;

[0024] When taking the phase voltage of phase C of the 10kV bus of the substation as the reference, take the difference The phase with the smallest difference is marked as phase C, and then the phase angles of the other two-phase currents are adjusted and marked as phase A and phase B in sequence according to the requirements of the positive phase sequence.

[0025] The object of the present invention can also be further realized by the following technical measures:

[0026] Preferably, the power factor angle of each 10kV line breaker interval of the substation described in step 1 is:

[0027]

[0028] (1) Where: P is the active power of each 10kV line breaker interval in the substation, and Q is the reactive power of each 10kV line breaker interval in the substation; φ represents phases A, B, and C; i represents the i-th line, where i ranges from 1 to n; the positive direction of P and Q is defined as follows: the direction in which the line load is sent from the substation bus to the line is defined as the positive direction.

[0029] Preferably, for the A-phase B-phase C-phase current of the j-th set of distribution measurement terminals on the i-th line of the 10kV line The calculation formula for the current phase angle is:

[0030]

[0031] In (2), is the phase angle of the A-phase B-phase C-phase current of the j-th set of distribution measurement terminals on the i-th line, where φ represents phases A, B, and C; represents the three-phase voltage of the 10kV bus of the substation represents the current flowing through the A-phase of the j-th set of distribution measurement terminals on the i-th line B-phase current C-phase current i represents the i-th line, where i ranges from 1 to n; j represents the j-th set of distribution measurement terminals on the i-th line, where j ranges from 1 to m.

[0032] Preferably, in steps 1 and 2, calculate the three-phase current phase angles of the distribution measurement terminals at the head end of the 10kV line and the power factor angle of the 10kV line interval in the substation

[0033]

[0034] The calculation formula for the difference between these two angles is that the qualified standard is within the range of ±20°.

[0035] Preferably, for the phase current phase angle of a certain phase of the j-th set of distribution measurement terminals on the i-th line downstream of the head end of a certain 10kV line and the phase current phase angle of the distribution measurement terminal at the head end

[0036]

[0037] The calculation formula for the difference The qualification standard is within the range of ±20°.

[0038] Preferably, the voltage level of the distribution line applicable to this method is 6 kV to 35 kV, and it is used in systems with ungrounded systems, arc suppression coil grounded systems, and small resistance grounded systems for 6 kV to 35 kV system grounding methods.

[0039] The method of the present invention can also be applied to the verification of the three-phase current phase sequence of a distribution automation terminal (FTU).

[0040] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0041] 1. The present invention collects the active power P and reactive power Q of the 10 kV line interval of the substation, calculates the power factor angle of this line, and at the same time collects the three-phase currents of phases A, B, and C of each distribution measurement terminal on this line. Based on the three-phase voltage of the 10 kV busbar of the substation, it calculates the three-phase current phase angles of the distribution measurement terminal at the head end of this line of the substation, and then calculates the difference between the phase angles of the currents of each phase of the distribution measurement terminal at the head end of this 10 kV line and the three-phase current power factor angle of the 10 kV line interval of the substation itself. Whether it is within the qualified range is used to judge the three-phase current phase sequence of phases A, B, and C of the distribution measurement terminal at the head end of this line. The discrimination is very accurate, which is beneficial for the 10 kV distribution network to quickly and accurately perform fault discrimination.

[0042] 2. The present invention is based on the three-phase voltage of the 10 kV busbar of the substation. By collecting the three-phase currents of phases A, B, and C of each distribution measurement terminal on this line, it calculates the three-phase current phase angles of each measurement point, and then calculates the difference between the phase angle of the current of phase A of the distribution measurement terminal downstream of the head end of this 10 kV line and the phase angle of the current of phase A of the distribution measurement terminal at the head end. Whether it is within the qualified range is used to judge the three-phase current phase sequence of phases A, B, and C of each distribution measurement terminal on this line. The discrimination is also very accurate, and the implementation scheme is simple and easy to operate, which is beneficial to improving the power supply reliability of the 10 kV distribution network.

[0043] 3. Since the power factor angle is calculated from the reactive power Q and active power P measured at a certain point on the line, it reflects the angle leading ahead by the angle, ahead by the angle, ahead by the angle at the measurement point of the line. Therefore, the method of the present invention can also verify whether the primary phase sequence marked on the 10 kV three-phase line is correct. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 is the single-line diagram of the connection of two 10 kV distribution lines of the present invention;

[0045] Figure 2 This is the flow chart for the present invention to verify the current phase and phase sequence discrimination of the 10 kV line distribution measurement terminal. Specific embodiments

[0046] The following will further illustrate the present invention in conjunction with the attached Figure 1 、 2 drawings and specific embodiments.

[0047] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Usually, the components of the embodiments of the present application described and illustrated herein can be arranged and designed in various different configurations.

[0048] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the present application claimed, but merely represents the selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts fall within the scope of protection of the present application.

[0049] In a 10 kV system that is an ungrounded system, an arc suppression coil grounded system, or a small resistance grounded system, based on wide-area synchronous information, a single-phase grounding or phase-to-phase fault discrimination system master station installed at the dispatching master station end or the substation end calculates the power factor angle of the 10 kV line interval of the substation in real time by collecting the three-phase voltages of the 10 kV bus of the substation and the active power P and reactive power Q of the 10 kV line interval. By collecting the three-phase currents of the distribution measurement terminal at the head end of the 10 kV line, the phase angle by which each phase current of the distribution measurement terminal at the head end of the 10 kV line of the substation lags behind each phase voltage of the 10 kV bus of the substation is calculated in real time. (abbreviated as the phase angle of the distribution measurement terminal); by comparing and calculating the power factor angle and the phase angle of the distribution measurement terminal at the head end of the 10 kV line of the difference between these two angles, it is judged whether the difference in angles meets the corresponding requirements, and a relay protection method for automatically verifying and checking the phase and phase sequence of each phase current of the measurement terminal on each 10 kV distribution line is realized.

[0050] The technical solution for verifying the current phase and phase sequence of the distribution measurement terminal by using the load power factor angle is as follows:

[0051] ⑴ At the dispatching master station or substation, a main station for single-phase grounding or phase-to-phase fault discrimination system (referred to as the main station system) is established to collect the three-phase voltages of the 10kV bus of the substation, the active power P and reactive power Q of the 10kV line interval, and calculate the power factor angle of the 10kV line interval of the substation in real time. Collect the three-phase currents of the distribution measurement terminal at the head end of the 10kV line, and calculate the phase angle of each phase current of the distribution measurement terminal at the head end of the 10kV line of the substation lagging behind the corresponding phase voltage of the 10kV bus of the substation in real time. (Referred to as the phase angle of the distribution measurement terminal); by comparing and calculating the power factor angle and the phase angle of the distribution measurement terminal at the head end of the 10kV line of the difference between these two angles, determine whether it meets the corresponding requirements; if the requirements are not met, it is judged as incorrect, and then the phase and phase sequence are adjusted; collect the three-phase currents of the distribution measurement terminals at other sampling points on the 10kV line, and calculate the phase angle of each phase current of the distribution measurement terminal lagging behind the corresponding phase voltage of the 10kV bus of the substation in real time. Compare with the phase angle of the distribution measurement terminal at the head end of this line and calculate the angle difference to determine whether it meets the corresponding requirements; if the requirements are not met, it indicates that the phase and phase sequence need to be adjusted. This method can also be used to collect fault information and conduct single-phase grounding fault and phase-to-phase fault discrimination.

[0052] ⑵ On the 10kV line, A, B, and C three-phase current PMU type current measurement devices (referred to as distribution measurement terminals) are installed at intervals as current measurement points to collect the A, B, and C phase PMU currents or zero-sequence currents at each measurement point on the line, and send them to the single-phase grounding or phase-to-phase fault discrimination main station system for PMU zero-sequence current 3I 0 、phase-to-phase fault、phase and other calculations;

[0053] ⑶ Install PMU type voltage measurement devices on the secondary side of PT on the 10kV bus or line of the substation to collect PMU three-phase voltages and zero-sequence voltage 3U 0 and calculate the three-phase voltage phase, etc.

[0054] The method for verifying the current phase and phase sequence of the distribution measurement terminal specifically includes the following steps:

[0055] 1. Step 1: Since the power factor angle is calculated from the reactive power Q and active power P measured at the substation line switch interval, it reflects the angle by which the substation line switch interval leads 、the angle by which leads 、the angle by which leads From this angle, this power factor angle is adopted. As a reference, check the three-phase current phase sequence of the distribution measurement terminal at the head end of the 10 kV line (since the distribution measurement terminal at the head end of the line is relatively close to the substation, the angles of the currents in each phase are similar to those of the currents in each phase of the 10 kV line switch interval of the substation); if the three-phase current phase sequence is incorrect, make corresponding adjustments:

[0056] Execute the following screening method on the master station system at the dispatching master station end or the substation end:

[0057] (1) Collect the three-phase voltages of the 10 kV bus of the substation and the active power P and reactive power Q of each 10 kV line interval in real time, and calculate the power factor angle of the 10 kV line interval of the substation in real time.

[0058] (2) Collect the three-phase currents of the distribution measurement terminal at the head end of the 10 kV line at the same moment as (1). Based on the three-phase voltages of the 10 kV bus of the substation, calculate in real time the phase angles by which the currents in each phase of the distribution measurement terminal at the head end of the 10 kV line of the substation lag the voltages in each phase of the 10 kV bus of the substation.

[0059] (3) Calculate the three-phase current phase angles of the distribution measurement terminal at the head end of the 10 kV line. And the power factor angle of the 10 kV line interval of the substation. The difference between these two angles. The calculation formula is:

[0060]

[0061] The calculated angle difference. The passing standard is within the range of ±20°.

[0062] During specific implementation, the phase angle of the A-phase current of the distribution measurement terminal at the head end of the 10 kV line can be compared and calculated. And the power factor angle. The difference between these two angles. (Since the three phases are symmetrical, comparison can be made with the A phase).

[0063] Judge whether the angle difference. Meets the passing standard:

[0064] ① When the passing standard is met, it means that the phase sequence of the currents in each phase of the distribution measurement terminal at the head end of the 10 kV line meets the requirements, and no phase sequence adjustment is required;

[0065] ② If the passing standard is not met, the phase sequence of the currents in each phase of this distribution measurement terminal needs to be adjusted:

[0066] Calculate the phase angle of a certain phase current of the distribution measurement terminal at the head end of the 10kV line With the power factor angle of the 10kV line interval in the substation The difference between these two angles When taking the voltage of phase A of the 10kV busbar in the substation as the reference, take the difference The phase with the smallest difference is marked as phase A, and then the phase currents of the other two phases are adjusted and marked as phase B and phase C in sequence according to the requirements of the positive phase sequence (in the vector diagram, in the clockwise direction).

[0067] Step 2, on the basis of confirming the phase sequence of the three-phase currents of the distribution measurement terminal at the head end, the phase sequence of the three-phase currents of each distribution measurement terminal downstream of the distribution measurement terminal at the head end can be further verified; the verification is carried out at the time point with the smallest load fluctuation, avoiding the power generation period of local power plants on the line to reduce the verification error.

[0068] The screening method is as follows:

[0069] The master station system at the dispatching master station end or the substation end:

[0070] ⑴ Collect the three-phase voltages of the 10kV busbar in the substation, the three-phase currents of the distribution measurement terminal at the head end of this line and each distribution measurement terminal downstream, and take the voltage of phase A of the 10kV busbar in the substation As the reference, calculate in real time the phase angle by which the current of each phase of each distribution measurement terminal on the 10kV line in the substation lags behind the voltage of each phase of the 10kV busbar in the substation

[0071] ⑵ Because the three phases are symmetrical, phase A is used for comparison. By comparing and calculating the phase angle of the current of phase A of each distribution measurement terminal downstream of the head end on the 10kV line And the phase angle of the current of phase A of the distribution measurement terminal at the head end The difference between these two angles

[0072] The calculated angle difference The qualified standard is ±20°;

[0073] ① When the qualified standard is met, it means that the phase sequence of the currents of each phase of the distribution measurement terminal downstream of the head end on the 10kV line meets the requirements, and no phase sequence adjustment is required;

[0074] ② If the qualified standard is not met, the phase sequence of the currents of each phase of this distribution measurement terminal needs to be adjusted:

[0075] Taking the voltage of phase A of the 10kV busbar in the substation As the reference, the phase angle of a certain phase current of the jth set of distribution measurement terminals downstream of the head end on the ith 10kV line The phase angle of the A-phase current of the distribution measurement terminal at the head end The difference between these two angles Take the difference Mark the phase with the smallest difference as the A-phase, and then adjust and mark the phases of the other two phases as the B-phase and C-phase in accordance with the requirements of the positive phase sequence.

[0076] Step 1 requires real-time collection of the active power P and reactive power Q of each 10kV line interval in the substation, and real-time calculation of the power factor angle of each 10kV line breaker interval in the substation It is:

[0077]

[0078] In formula (5): P is the active power of each 10kV line breaker interval in the substation, Q is the reactive power of each 10kV line breaker interval in the substation; φ is the A-phase, B-phase, and C-phase; i is the i-th line, and i ranges from 1 to n. The positive directions of P and Q are specified as follows: Generally, it is set that the line load (P and Q) is sent from the substation bus to the line as + (positive direction), that is, the active power P is sent from the substation bus to the line as + (positive direction), and the reactive power Q is sent from the substation bus to the line as + (positive direction).

[0079] Steps 1 and 2 require calculating the A-phase B-phase C-phase current of the j-th set of distribution measurement terminals on the i-th 10kV line The calculation formula is:

[0080]

[0081] In (6), φ i.φj is the phase angle of the A-phase B-phase C-phase current of the j-th set of distribution measurement terminals on the i-th line, is the three-phase voltage of the 10kV bus of the substation are the currents flowing through the A-phase current B-phase current C-phase current of the j-th set of distribution measurement terminals on the i-th line respectively; φ is the A-phase, B-phase, and C-phase; i is the i-th line, and i ranges from 1 to n; j is the j-th set of distribution measurement terminals on the i-th line, and j ranges from 1 to m.

[0082] The voltage level of the distribution line to which the present invention is applied is 6 kV to 35 kV, and it is used in systems with grounding methods of ungrounded system, arc suppression coil grounded system, and small resistance grounded system for 6 kV to 35 kV. The method of the present invention can also be applied to the verification of the three-phase current phase sequence of a distribution automation terminal (FTU).

[0083] In the following embodiments, 10 kV is taken as an example.

[0084] Embodiment 1: Verification of the three-phase current phase sequence of the distribution measurement terminals at the heads of each 10 kV line in a substation:

[0085] A certain substation has 6 10 kV lines. The active power P and reactive power Q measured at each 10 kV line interval are obtained. According to P and Q, the power factor angle is calculated as shown in Table 1; the phase of the current of phase A at the head of each 10 kV line of the distribution measurement terminal is measured Then the power factor angle is calculated, and the difference △φ from the phase of the current of phase A at the head of the distribution measurement terminal of the line is obtained. i.a1 . The phase verification situation is shown in Table 1.

[0086] Table 1 Verification table of the three-phase current phase sequence of the distribution measurement terminals at the heads of 10 kV lines in a certain substation

[0087]

[0088] Embodiment 2: Verification of the three-phase current phase sequence of the distribution measurement terminals downstream of the head of the i-th 10 kV line in a certain substation:

[0089] A total of 7 groups of distribution measurement terminals are installed on the i-th 10 kV line in a certain substation, which are installed on pole No. 1, pole No. 43, pole No. 69, pole No. 8 of branch 1, pole No. 27 of branch 1, pole No. 41 of branch 1, and pole No. 13 of branch 2. The phase of the current of each phase at each measurement point of this line is measured at night, and then the phase angle with the current of phase A at the head of the distribution measurement terminal is calculated. If it is within the range of ±20°, the verification is correct. The phase verification situation is shown in Table 2.

[0090] Table 2 Verification table of the three-phase current phase sequence of the distribution measurement terminals downstream of the head of a certain 10 kV line in a certain substation

[0091]

[0092]

[0093] In addition to the above embodiments, the present invention may have other embodiments. All technical solutions formed by equivalent replacement or equivalent transformation fall within the protection scope required by the present invention.

Claims

1. A method for checking the phase sequence of terminal current in a circuit by using load power factor angle, characterized in that: The following steps are involved: Step 1: (1) Collect the three-phase voltage of the 10kV busbar of the substation, the active power P and reactive power Q of each 10kV line interval in real time, and calculate the power factor angle of the 10kV line interval of the substation in real time. ⑵ Collect the three-phase current of the distribution measurement terminal at the head end of the 10kV line at the same time as ⑴, and use the three-phase voltage of the 10kV busbar of the substation as the reference to calculate in real time the phase angle of the phase current of the distribution measurement terminal at the head end of the 10kV line of the substation lagging behind the phase voltage of the 10kV busbar of the substation ⑶ Calculate the phase angle of the phase current at the distribution measurement terminal at the head end of the 10kV line and the power factor angle of 10kV line interval of substation The difference between these two angles Determine whether the eligibility criteria are met: ① When the qualified standard is met, it means that the phase sequence of each phase current at the distribution measurement terminal at the head end of the 10kV line is correct; ② If the qualified standard is not met, it means an error has occurred and the phase sequence of each phase current of the power distribution measurement terminal needs to be adjusted and corrected. The adjustment and correction method is: When the substation 10kV bus phase A voltage is used as the reference, the difference is taken The smallest phase is marked as phase A, and then the other two phases are adjusted in sequence according to the positive phase sequence requirements and marked as phase B and phase C; When the substation 10kV busbar B phase voltage is used as the reference, take the difference The smallest phase is marked as phase B, and then the other two phases are adjusted in sequence according to the positive phase sequence requirements and marked as phase C and phase A; When the substation 10kV bus phase C voltage is used as the reference, the difference is taken The smallest phase is marked as phase C, and then the other two phases are adjusted in sequence according to the positive phase sequence requirements and marked as phase A and phase B; Step 2: on the basis of confirming the phase sequence of the three-phase current at the head-end distribution measurement terminal, further verify the phase sequence of the three-phase current at other sampling points, that is, the phase sequence of the three-phase current at each distribution measurement terminal downstream of the head-end distribution measurement terminal; Here’s how: ⑴ Collect the three-phase voltage of the 10kV busbar of the substation and the three-phase current of each distribution measurement terminal downstream of the distribution measurement terminal at the head end of the line. Take the phase voltage of the 10kV busbar of the substation as the reference, and calculate the phase angle of the phase current of each distribution measurement terminal on the 10kV line of the substation lagging behind the phase voltage of the 10kV busbar of the substation in real time. (2) Collect the phase current of the distribution measurement terminal at other sampling points on the 10kV line, and calculate in real time the phase angle of the three-phase current of the distribution measurement terminal lagging behind the phase voltage of the 10kV busbar of the substation Phase angle with the power distribution measurement terminal at the head end of this line Compare and calculate the difference Determine whether the eligibility criteria are met; ① If the qualified standard is met, it means that the phase and phase sequence of each phase current of the distribution measurement terminal downstream of the head end of the 10kV line are correct; ② If the qualified standards are not met, the phase sequence of each phase current of the power distribution measurement terminal needs to be adjusted and corrected; The adjustment and correction methods are: When the substation 10kV bus phase A voltage is used as the reference, the difference is taken The smallest phase is marked as phase A, and then the other two phases are adjusted in sequence according to the positive phase sequence requirements and marked as phase B and phase C; When the substation 10kV busbar B phase voltage is used as the reference, take the difference The smallest phase is marked as phase B, and then the other two phases are adjusted in sequence according to the positive phase sequence requirements and marked as phase C and phase A; When the substation 10kV bus phase C voltage is used as the reference, the difference is taken The smallest phase is marked as phase C, and then the phases of the other two phases are adjusted in sequence according to the positive phase sequence requirements and marked as phase A and phase B.

2. The method for measuring the phase and sequence of terminal current by using load power factor angle to check the circuit as claimed in claim 1 is characterized in that: Step 1: The power factor angle of each 10kV line breaker bay in the substation for: (1) Where: P is the active power of each 10 kV line breaker bay in the substation; Q is the reactive power of each 10 kV line breaker bay in the substation; φ represents phase A, phase B, and phase C; i represents the i-th line, and i is 1 to n; the positive direction of P and Q is defined as follows: the line load is set to be sent from the substation bus to the line in the positive direction.

3. The method for checking the phase sequence of the terminal current by using the load power factor angle of claim 1 is characterized in that: Phase A of the jth distribution measurement terminal on the ith line of a 10kV line Phase B Phase C current The current phase angle The calculation formula is: (2) Phase A of the jth distribution measurement terminal of the i-th line Phase B Phase C current The phase angle, φ represents phase A, phase B, and phase C; Represents the three-phase voltage of the 10kV busbar of the substation Represents the current flowing through the phase A of the jth distribution measurement terminal of the i-th line Phase B current Phase C current i represents the i-th line, i ranges from 1 to n; j represents the jth group of distribution measurement terminals on the i-th line, and j is 1 to m.

4. The method for checking the phase sequence of the terminal current by using the load power factor angle of claim 1, characterized in that: In steps 1 and 2, calculate the three-phase current phase angle of the distribution measurement terminal at the head end of the 10kV line and the power factor angle of 10kV line interval of substation The difference between these two angles The calculation formula is: Calculated angle difference The acceptance standard is within ±20°.

5. The method for checking the phase sequence of the terminal current measured by the load power factor angle according to claim 1 is characterized in that: The phase angle of the current of a certain phase at the jth distribution measurement terminal of the i-th line downstream of a 10kV line The phase angle of the phase current of the distribution measurement terminal at the head end The difference between these two angles The calculation formula is: Calculated angle difference The acceptance standard is within ±20°.

6. The method for checking the phase sequence of the terminal current measured by the load power factor angle according to claim 1, characterized in that: The applicable voltage level of the distribution line is 6kV~35kV. The grounding methods used in the 6kV~35kV system are ungrounded system, arc suppression coil grounding system, and low resistance grounding system.

Images