Monitoring and alarm methods for three-phase load imbalance

Abstract

The application discloses a kind of three-phase load imbalance monitoring alarm method.The method comprises: obtaining the current data, power data and appeal work order data of target area at multiple sampling time points;According to the current data and power data, determine the three-phase load imbalance type of target area;According to three-phase load imbalance type and appeal work order data, determine whether to send risk alarm to target area.The technical scheme provided by the embodiment of the application obtains the current data and power data of multiple sampling time points in the target area, thereby obtaining the working condition of the distribution transformer in the target area at multiple sampling time points, and then determining the three-phase load imbalance type of the target area.Combined with the appeal work order data fed back by the actual experience of users in the target area, the power supply condition in the target area can be judged more accurately, and the target area needing to send risk alarm is prompted, so that the technical effect of improving the management efficiency of power grid and the satisfaction of users is realized.

Description

Technical Field

[0001] This invention relates to the field of power system technology, and in particular to a method for monitoring and alarming three-phase load imbalance. Background Technology

[0002] With the rapid development of the power industry and the continuous expansion of the power grid, the monitoring and management of low-voltage data in the power grid system is becoming increasingly intelligent and systematic. Currently, low-voltage data monitoring in the power grid system often suffers from incompleteness and untimeliness, directly leading to difficulties for power grid managers in accurately grasping the operating status of the power grid, thereby affecting the stability of the power grid and customer satisfaction. Summary of the Invention

[0003] This invention provides a method for monitoring and alarming three-phase load imbalance, which can accurately determine the degree of three-phase load imbalance in a distribution area and issue reasonable alarms, thereby improving the overall operating efficiency of the power grid and customer satisfaction.

[0004] According to one aspect of the present invention, a method for monitoring and alarming three-phase load imbalance is provided, comprising:

[0005] Acquire current data, power data, and work order data for the target transformer area at multiple sampling times;

[0006] The three-phase load imbalance type of the target distribution area is determined based on the current data and the power data; the three-phase load imbalance type includes distribution areas with daily general three-phase load imbalance, distribution areas with daily severe three-phase load imbalance, distribution areas with monthly general three-phase load imbalance, and distribution areas with monthly severe three-phase load imbalance.

[0007] Based on the three-phase load imbalance type and the requested work order data, determine whether to send a risk alarm to the target transformer area.

[0008] Optionally, the type of three-phase load imbalance in the target distribution area is determined based on the current data and the power data, including:

[0009] The load rate and three-phase imbalance of the target transformer area are determined based on the current data and the power data.

[0010] The type of three-phase load imbalance in the target distribution area is determined based on the load rate, the three-phase imbalance, and the wiring type of the distribution transformer in the target distribution area.

[0011] Optionally, the formula for calculating the load rate is:

[0012]

[0013] The formula for calculating the three-phase unbalance is as follows:

[0014]

[0015] Where P is the load factor, I0 is the peak current on the secondary side of the distribution transformer in the target area, CT is the ratio of the primary phase current to the secondary phase current of the distribution transformer, and W is the apparent power of the distribution transformer. I1 represents the three-phase unbalance of the distribution transformer, I2 represents the minimum phase current on the secondary side of the distribution transformer, and I3 represents the maximum phase current on the secondary side of the distribution transformer.

[0016] Optionally, the wiring type of the distribution transformer is Yyn0. The three-phase load imbalance type of the target distribution area is determined based on the load rate, the three-phase imbalance degree, and the wiring type of the distribution transformer in the target area, including:

[0017] If the load rate at each of the n consecutive sampling times is greater than the first load threshold, and the three-phase imbalance is greater than the first imbalance threshold, then the target transformer area is determined to be a transformer area with severe three-phase load imbalance on that day; where n is an integer greater than 5.

[0018] If the load rate at each of the n consecutive sampling times is greater than the second load threshold, the three-phase imbalance is greater than the second imbalance threshold, and the target transformer area is not a severely unbalanced three-phase load area, then the target transformer area is determined to be a generally unbalanced three-phase load area on that day.

[0019] Optionally, the wiring type of the distribution transformer is Dyn11. The three-phase load imbalance type of the target distribution area is determined based on the load rate, the three-phase imbalance degree, and the wiring type of the distribution transformer in the target distribution area, including:

[0020] If the load rate at each of the n consecutive sampling times is greater than the first load threshold, and the three-phase imbalance is greater than the third imbalance threshold, then the target transformer area is determined to be a severely unbalanced three-phase load area on that day; where n is an integer greater than 5;

[0021] If the load rate at each of the n consecutive sampling times is greater than the first load threshold, the three-phase imbalance is greater than the first imbalance threshold, and the target transformer area is not a severely unbalanced three-phase transformer area on that day, then the target transformer area is determined to be a generally unbalanced three-phase transformer area on that day.

[0022] Optionally, determining the three-phase load imbalance type of the target distribution area based on the load rate, the three-phase imbalance degree, and the wiring type of the distribution transformer in the target distribution area further includes:

[0023] If the number of times the target distribution area is the daily severe three-phase load imbalance distribution area within a month is greater than the first preset number, then the target distribution area is determined to be the monthly severe three-phase load imbalance distribution area for that month.

[0024] If the number of times the target distribution area is a daily general three-phase load imbalance area or a daily severe three-phase load imbalance area within a month is greater than the second preset number and less than the first preset number, then the target distribution area is determined to be a monthly general three-phase load imbalance area for that month; wherein, the second preset number is less than the first preset number.

[0025] Optionally, the type of three-phase load imbalance in the target distribution area is determined based on the current data and the power data, including:

[0026] Based on the current data, determine the daily maximum load rate and three-phase imbalance of multiple outgoing lines within the target transformer area, as well as the peak time corresponding to the daily maximum load rate of the outgoing lines;

[0027] Target candidates are selected based on the relationship between the maximum daily load rate and the load rate threshold.

[0028] Based on the three-phase unbalance of m sampling points before and after the peak time, the three-phase load unbalance type of the target outgoing line is determined; where m is an integer greater than 8.

[0029] Optionally, the formula for calculating the maximum daily load rate is:

[0030]

[0031] in, I3 is the maximum daily load rate, I3 is the maximum phase current of the outgoing line on the same day, and a is the overcurrent setting.

[0032] Optionally, the three-phase load imbalance type of the target outgoing line is determined based on the three-phase imbalance of m sampling points before and after the peak time; where m is an integer greater than 8.

[0033] If the three-phase imbalance of the m sampling points before and after the peak time of the target line is greater than the third imbalance threshold, and the daily maximum load rate of the target line is greater than the first load threshold and less than the second load threshold, then the target line is determined to be a general three-phase load imbalance line.

[0034] If the three-phase imbalance of the m sampling points before and after the peak time of the target line is greater than the third imbalance threshold, and the daily maximum load rate of the target line is greater than or equal to the second load threshold, then the target line is determined to be a line with severe three-phase load imbalance.

[0035] Optionally, the request work order data includes: low voltage feedback work orders, low voltage complaint work orders, power outage complaint work orders, and power outage feedback work orders; based on the three-phase load imbalance type and the request work order data, determining whether to send a risk alarm to the target transformer area includes:

[0036] If the target distribution area receives the low voltage complaint work order on the same day, and the distribution area is a distribution area with severe three-phase load imbalance on that day, a low voltage complaint risk alarm will be sent to the target distribution area.

[0037] If the target distribution area receives the low voltage complaint work order on the same day, and the distribution area is a distribution area with severe three-phase load imbalance on that day, then a low voltage complaint risk alarm will be sent to the target distribution area.

[0038] If the target distribution area is a severely unbalanced three-phase load area on that day, a low voltage alarm will be sent to the target distribution area.

[0039] If the target transformer area receives the power outage complaint work order on the same day, the target transformer area is a transformer area with severe three-phase load imbalance on that day, and the number of times the target transformer area received the power outage complaint work order in the six months prior to the current month is greater than x, then a medium-risk power outage complaint alarm is sent to the target transformer area; where x is an integer greater than 4.

[0040] If the target distribution area is a severely unbalanced three-phase load distribution area on the current day, and the number of outage feedback work orders received in the previous six months is greater than y, then a medium-risk outage problem alarm will be sent to the target distribution area; where y is an integer greater than 1.

[0041] If the target transformer area receives a power outage complaint work order on the same day, and the target transformer area is a daily area with severe three-phase load imbalance, and the target transformer area is a monthly area with severe three-phase load imbalance, and the number of power outage complaint work orders received by the target transformer area in the six months prior to the current month is greater than z, then a high-risk power outage complaint alarm will be sent to the target transformer area; where z is an integer greater than 9.

[0042] If the target distribution area is a daily area with severe three-phase load imbalance, and the target distribution area is a monthly area with severe three-phase load imbalance, then a high-risk power outage alarm will be sent to the target distribution area.

[0043] The technical solution provided by this invention acquires current and power data for a target distribution area at multiple sampling times throughout the day, thereby determining the operating status of the distribution transformer within the target area at those times and identifying the type of three-phase load imbalance. Combined with work order data reflecting user feedback within the target area, the system can more accurately assess the power supply status and issue alarms to areas requiring risk alerts, thus improving grid management efficiency and user satisfaction.

[0044] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 A flowchart illustrating a three-phase load imbalance monitoring and alarm method provided in an embodiment of the present invention;

[0047] Figure 2 A flowchart of another three-phase load imbalance monitoring and alarm method provided in an embodiment of the present invention;

[0048] Figure 3 A flowchart of another three-phase load imbalance monitoring and alarm method provided in an embodiment of the present invention;

[0049] Figure 4 A flowchart of another three-phase load imbalance monitoring and alarm method provided in an embodiment of the present invention;

[0050] Figure 5 A flowchart of another three-phase load imbalance monitoring and alarm method provided in an embodiment of the present invention;

[0051] Figure 6 A flowchart of another three-phase load imbalance monitoring and alarm method provided in an embodiment of the present invention;

[0052] Figure 7 A flowchart of another three-phase load imbalance monitoring and alarm method provided in an embodiment of the present invention;

[0053] Figure 8A flowchart of another three-phase load imbalance monitoring and alarm method provided in an embodiment of the present invention. Detailed Implementation

[0054] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0055] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0056] Figure 1 This is a flowchart illustrating a method for monitoring and alarming three-phase load imbalance according to an embodiment of the present invention. This embodiment is applicable to monitoring three-phase load imbalance in distribution network areas. The method can be executed by a three-phase load imbalance monitoring device, which can be implemented in hardware and / or software and configured in a power grid management platform system. Figure 1 As shown, the method includes:

[0057] S110. Acquire current data, power data, and work order data of the target transformer area at multiple sampling times;

[0058] Specifically, the target distribution area can be the area supplied and distributed by a single distribution transformer in the power grid system. Current data can be the three-phase current at both the primary and secondary sides of the distribution transformer. Power data can be the apparent power of the distribution transformer, which can be collected through the power company's internal metering system. Request work order data can be user-reported electricity demand calls received within the target distribution area, which can be collected through the power company's grid management platform system. The number of sampling times for the target distribution area will vary depending on the time interval between sampling moments. Multiple sampling moments can be set at equal intervals. For example, the time interval between each sampling moment can be 15 minutes. Correspondingly, request work order data, as well as the apparent power and current data of the distribution transformer, will be collected every 15 minutes within the target distribution area. If the time interval between sampling moments is too long, the current data obtained in each sampling will be significantly affected by grid fluctuations, affecting the accuracy of the final judgment; if the time interval between sampling moments is too short, the amount of current data obtained will be large, affecting the judgment efficiency.

[0059] S120. Determine the type of three-phase load imbalance in the target distribution area based on current and power data;

[0060] Specifically, the three-phase load balance type in a power system is one of the important indicators for judging the power quality within a power supply area. Differences in electricity consumption among users within a target distribution area, differences in electricity consumption periods, and other reasons related to electricity consumption can all cause varying degrees of three-phase load imbalance within the target distribution area. Multiple sets of current data are acquired at multiple sampling times throughout the day. By calculating and analyzing these multiple sets of current and power data, the operating status of the distribution transformers within the target distribution area at multiple sampling times can be determined, thereby identifying the type of three-phase load imbalance in the target distribution area.

[0061] S130. Based on the type of three-phase load imbalance and the work order data, determine whether to send a risk alarm to the target transformer area.

[0062] Specifically, the three-phase load imbalance type objectively reflects the power supply status of the target distribution area based on the grid operation data within that area. The three-phase load imbalance type can be categorized as daily general three-phase load imbalance area, daily severe three-phase load imbalance area, monthly general three-phase load imbalance area, and monthly severe three-phase load imbalance area. The work order data reflects the power supply status of the target distribution area based on feedback from users' actual experiences within that area. Therefore, by combining the grid operation data and user feedback within the target distribution area, a comprehensive judgment can be made as to whether a risk alarm needs to be sent to the target distribution area, thereby improving grid management efficiency and user satisfaction.

[0063] The technical solution provided by this invention acquires current and power data from multiple sampling times within a target distribution area, thereby determining the operating status of the distribution transformer within that area and identifying the type of three-phase load imbalance. Combined with feedback from user complaints within the target area, the system more accurately assesses the power supply status and sends alarm notifications to areas requiring risk alerts, thus improving grid management efficiency and user satisfaction.

[0064] Optionally, Figure 2 A flowchart illustrating another method for monitoring and alarming three-phase load imbalance provided in this embodiment of the invention. Based on the above embodiment, see [link to relevant documentation]. Figure 2 The method includes:

[0065] S210. Obtain current data, power data, and work order data for the target transformer area at multiple sampling times;

[0066] S220. Determine the load rate and three-phase imbalance of the target transformer area based on current and power data.

[0067] Specifically, load factor and three-phase imbalance are two important parameters reflecting the power supply quality of distribution transformers. Load factor is the ratio of the actual load value to the power of the distribution transformer during operation; three-phase imbalance is the degree of phase inconsistency between the three-phase currents on the secondary side. At each sampling moment, a set of current and power data for the distribution transformer within the target area can be obtained. Based on this current and power data, the load factor and three-phase imbalance of the target area at each sampling moment can be calculated. The current data can include the peak current on the secondary side of the distribution transformer and the phase currents of phases A, B, and C on the secondary side of the distribution transformer.

[0068] For example, the load rate of the target station area at a sampling time can be calculated by equation (1).

[0069] (1)

[0070] The three-phase imbalance of the target station area at a sampling time can be calculated by equation (2).

[0071] (2)

[0072] Where P is the load factor, I0 is the peak current on the secondary side of the distribution transformer in the target area, CT is the ratio of the primary phase current to the secondary phase current of the distribution transformer, and W is the apparent power of the distribution transformer. I1 represents the three-phase unbalance of the distribution transformer, I2 represents the minimum phase current among phases A, B, and C on the secondary side of the distribution transformer, and I3 represents the maximum phase current among phases A, B, and C on the secondary side of the distribution transformer.

[0073] S230. Determine the type of three-phase load imbalance in the target distribution area based on the load rate, three-phase imbalance degree, and wiring type of the distribution transformer in the target distribution area.

[0074] Specifically, the wiring types of distribution transformers in different target areas may differ. When determining the three-phase load imbalance type of a target area, different judgment criteria can be set for each target area based on the wiring type of the distribution transformer, thereby improving the accuracy of the three-phase load imbalance type judgment. For example, the wiring type of the distribution transformer can be Yyn0 or Dyn11. Yyn0 wiring means that both the primary and secondary sides of the distribution transformer are star-connected, the neutral point of the secondary side has a lead-out, and the phase difference between the primary and secondary sides is 0 degrees. Dyn11 wiring means that the primary side of the distribution transformer is delta-connected, the secondary side is star-connected, the neutral point of the secondary side has a lead-out, and the phase difference between the primary and secondary sides is 30 degrees. In a star connection, the ends of the windings of phases A, B, and C are connected together to form a common point, i.e., the neutral point. The delta connection method involves connecting phases A, B, and C sequentially end to end, and then drawing out each connection point as three phase lines.

[0075] S240. Based on the type of three-phase load imbalance and the work order data, determine whether to send a risk alarm to the target transformer area.

[0076] Optionally, Figure 3 A flowchart illustrating another method for monitoring and alarming three-phase load imbalance provided in this embodiment of the invention. Based on the above embodiment, see [link to relevant documentation]. Figure 3 When the distribution transformer is of the Yyn0 connection type, the method includes:

[0077] S310. Acquire current data, power data, and work order data of the target transformer area at multiple sampling times;

[0078] S320. Determine the load rate and three-phase imbalance of the target transformer area based on current and power data.

[0079] S330. If the load rate at each of the n consecutive sampling times is greater than the first load threshold and the three-phase imbalance is greater than the first imbalance threshold, then the target transformer area is determined to be a severely unbalanced three-phase load area on that day; where n is an integer greater than 5.

[0080] Specifically, with a 15-minute time interval between each sampling moment, the number of sampling moments for the target distribution area within a day is 96. Correspondingly, if, within these 96 sampling moments, the load rate of the Yyn0-connected distribution transformer is greater than the first load threshold and the three-phase imbalance is greater than the first imbalance threshold for n consecutive sampling moments, this can be equivalent to the Yyn0-connected distribution transformer exceeding the first load threshold and the three-phase imbalance exceeding the first imbalance threshold within 15×n minutes. Therefore, the distribution transformer can be determined as a Yyn0-connected target distribution area, and the day is considered a severely unbalanced three-phase load area. For example, the first load threshold can be 78%, and the first imbalance threshold can be 28%. It should be noted that n can be adaptively set according to the time interval between sampling moments.

[0081] S340. If the load rate at n consecutive sampling times is greater than the second load threshold, the three-phase imbalance is greater than the second imbalance threshold, and the target area is not a severely unbalanced three-phase load area on a given day, then the target area on that day is determined to be a generally unbalanced three-phase load area on a given day.

[0082] Specifically, if the target distribution area with a Yyn0 connection is not a severely unbalanced three-phase load area, it is necessary to further determine whether the target distribution area is a generally unbalanced three-phase load area. If, in 96 sampling times, the load rate of the Yyn0 connection type distribution transformer is greater than the second load threshold and the three-phase imbalance degree is greater than the second imbalance threshold for n consecutive sampling times, this can be equivalent to the load rate of the Yyn0 connection type distribution transformer exceeding the second load threshold and the three-phase imbalance degree exceeding the second imbalance threshold within 15×n minutes. Therefore, it can be determined that the distribution transformer is a Yyn0 connection type target distribution area, and that the area is a generally unbalanced three-phase load area on that day. For example, the second load threshold can be 58%, and the second imbalance threshold can be 13%.

[0083] S350: Based on the type of three-phase load imbalance and the work order data, determine whether to send a risk alarm to the target transformer area.

[0084] Optionally, Figure 4 A flowchart illustrating another method for monitoring and alarming three-phase load imbalance provided in this embodiment of the invention. Based on the above embodiment, see [link to relevant documentation]. Figure 4 When the distribution transformer is of the Dyn11 connection type, the method includes:

[0085] S410: Acquire current data, power data, and work order data for the target distribution area at multiple sampling times;

[0086] S420. Determine the load rate and three-phase imbalance of the target transformer area based on current and power data.

[0087] S430. If the load rate at each of the n consecutive sampling times is greater than the first load threshold and the three-phase imbalance is greater than the third imbalance threshold, then the target transformer area is determined to be a severely unbalanced three-phase load area on that day; where n is an integer greater than 5.

[0088] Specifically, with a 15-minute time interval between each sampling moment, the number of sampling moments for the target distribution area within a day is 96. Correspondingly, if, within these 96 sampling moments, for n consecutive sampling moments, the load rate of the Dyn11-connected distribution transformer is greater than the first load threshold, and the three-phase imbalance is greater than the third imbalance threshold, this can be equivalent to the load rate of the Dyn11-connected distribution transformer exceeding the first load threshold and the three-phase imbalance exceeding the third imbalance threshold within 15×n minutes. Therefore, it can be determined that the target distribution area with the Dyn11-connected type is a severely unbalanced three-phase load area on that day. For example, the third imbalance threshold can be 48%.

[0089] S440. If the load rate at n consecutive sampling times is greater than the first load threshold, the three-phase imbalance is greater than the first imbalance threshold, and the target area is not a severely unbalanced three-phase load area on a given day, then the target area on that day is determined to be a generally unbalanced three-phase load area on a given day.

[0090] Specifically, if the target distribution area with a Dyn11 connection type transformer is not a severely unbalanced three-phase load area, it is necessary to further determine whether the target distribution area is a generally unbalanced three-phase load area. If, in 96 sampling times, the load rate of the Dyn11 connection type transformer is greater than the first load threshold and the three-phase imbalance degree is greater than the second imbalance threshold for n consecutive sampling times, this can be equivalent to the load rate of the Dyn11 connection type transformer exceeding the first load threshold and the three-phase imbalance degree exceeding the second imbalance threshold within 15×n minutes. Therefore, it can be determined that the distribution transformer is a Dyn11 connection type target distribution area, and the area is a generally unbalanced three-phase load area on that day.

[0091] S450: Based on the type of three-phase load imbalance and the work order data, determine whether to send a risk alarm to the target transformer area.

[0092] Optionally, Figure 5 A flowchart illustrating another method for monitoring and alarming three-phase load imbalance provided in this embodiment of the invention. Based on the above embodiment, see [link to relevant documentation]. Figure 5After determining the three-phase load imbalance type of the target distribution area based on the load rate, three-phase imbalance degree, and wiring type of the distribution transformers within the target area, the method further includes:

[0093] S510. If the number of times the target area is a severely unbalanced three-phase load area within a month is greater than the first preset number, then the target area is determined to be a severely unbalanced three-phase load area for the current month.

[0094] Specifically, within the target distribution area, statistics are compiled starting from the beginning of each calendar month. If the number of times a distribution area is identified as having severe daily three-phase load imbalance in a given month exceeds a first preset number, the target distribution area can be determined to be a severe monthly three-phase load imbalance distribution area for that month. For example, the first preset number can be 10.

[0095] S520. If the number of times the target transformer area is a daily general three-phase load imbalance transformer area or a daily severe three-phase load imbalance transformer area within a month is greater than the second preset number but less than the first preset number, then the target transformer area is determined to be a monthly general three-phase load imbalance transformer area for that month; wherein, the second preset number is less than the first preset number.

[0096] Specifically, before a target transformer area is identified as a severely unbalanced three-phase load area for the month, it is necessary to determine whether the target transformer area is a generally unbalanced three-phase load area for the month. For example, the first preset number of occurrences can be 10, and the second preset number of occurrences can be 8. Within the target transformer area, starting from the beginning of each calendar month, if the target transformer area is identified as a generally unbalanced three-phase load area or a severely unbalanced three-phase load area for the day more than 8 times but less than 10 times within a month, the target transformer area can be determined to be a generally unbalanced three-phase load area for the month.

[0097] Optionally, Figure 6 A flowchart illustrating another method for monitoring and alarming three-phase load imbalance provided in this embodiment of the invention. Based on the above embodiment, see [link to relevant documentation]. Figure 6 The method includes:

[0098] S610: Obtain current data, power data, and work order data for the target distribution area at multiple sampling times;

[0099] S620. Determine the daily maximum load rate and three-phase imbalance of multiple outgoing lines in the target area based on the current data, as well as the peak time corresponding to the daily maximum load rate of the outgoing lines.

[0100] Specifically, the outgoing line can be a subordinate branch area within the target transformer area. Correspondingly, the obtained current data can be the phase currents of phases A, B, and C on the load side of the outgoing line. The daily maximum load rate of the outgoing line can be calculated using equation (3).

[0101] (3)

[0102] Among them, P max I3 represents the maximum daily load rate, I3 represents the maximum phase current at all sampling times on the outgoing line on that day, and a represents the overcurrent setting. The sampling time corresponding to the maximum daily load rate of the outgoing line is the peak time.

[0103] The three-phase imbalance of the outgoing line can be obtained according to equation (4).

[0104] (4)

[0105] Where ε is the three-phase unbalance of the outgoing line, I4 is the minimum phase current among the three phases A, B, and C on the load side of the outgoing line, and I5 is the maximum phase current among the three phases A, B, and C on the load side of the outgoing line.

[0106] S630. Filter target candidates based on the relationship between the daily maximum load rate and the load rate threshold;

[0107] Specifically, the three-phase load imbalance types of outgoing lines can be divided into: general three-phase load imbalance outgoing lines and severe three-phase load imbalance outgoing lines. For these two types of outgoing lines, the corresponding daily maximum load rate has different ranges. Therefore, it is necessary to first filter out the target outgoing lines corresponding to the three-phase load imbalance type based on the relationship between the daily maximum load rate and the load rate threshold, and then further determine whether the target outgoing lines are of the corresponding type of three-phase load imbalance outgoing lines.

[0108] S640. Based on the three-phase unbalance of m sampling points before and after the peak time, determine the three-phase load unbalance type of the target outgoing line; where m is an integer greater than 8.

[0109] Specifically, after selecting the target outgoing line of the corresponding type, the three-phase unbalance of m sampling points before and after the peak time of the outgoing line can be used to determine whether the target outgoing line belongs to the corresponding type of three-phase load unbalanced outgoing line.

[0110] Optionally, Figure 7 A flowchart illustrating another method for monitoring and alarming three-phase load imbalance provided in this embodiment of the invention. Based on the above embodiment, see [link to relevant documentation]. Figure 7 The method includes:

[0111] S710: Acquire current data, power data, and work order data of the target transformer area at multiple sampling times;

[0112] S720. Determine the daily maximum load rate and three-phase imbalance of multiple outgoing lines in the target area based on the current data, as well as the peak time corresponding to the daily maximum load rate of the outgoing lines.

[0113] S730. If the three-phase imbalance of the m sampling points before and after the peak time of the target line is greater than the third imbalance threshold, and the daily maximum load rate of the target line is greater than the first load threshold and less than the second load threshold, then the target line is determined to be a general three-phase load imbalance line.

[0114] Specifically, if the maximum load rate of the m sampling points before and after the peak time of the outgoing line is greater than the first load threshold but less than the second load threshold, the outgoing line can be determined to be a target outgoing line for general three-phase load imbalance. Further, if the three-phase imbalance degree of the m sampling points before and after the peak time of the target outgoing line for general three-phase load imbalance is greater than the third imbalance threshold, the target outgoing line for general three-phase load imbalance can be determined to be a target outgoing line for general three-phase load imbalance. For example, the first load threshold can be 75%, the second load threshold can be 80%, and the third imbalance threshold can be 48%. It should be noted that the first load threshold, the second load threshold, and the third imbalance threshold can be adjusted according to the actual operating conditions corresponding to the outgoing line.

[0115] S740. If the three-phase imbalance of the m sampling points before and after the peak time of the target line is greater than the third imbalance threshold, and the daily maximum load rate of the target line is greater than or equal to the second load threshold, then the target line is determined to be a line with severe three-phase load imbalance.

[0116] Specifically, if the maximum load rate of the m sampling points before and after the peak time of the outgoing line is greater than or equal to the second load threshold, the outgoing line can be determined to be a target outgoing line with severe three-phase load imbalance. Furthermore, if the three-phase imbalance degree of the m sampling points before and after the peak time of the target outgoing line with severe three-phase load imbalance is greater than the third imbalance threshold, the target outgoing line with severe three-phase load imbalance can be determined to be an outgoing line with severe three-phase load imbalance.

[0117] Optionally, Figure 8 A flowchart illustrating another method for monitoring and alarming three-phase load imbalance provided in this embodiment of the invention. Based on the above embodiment, see [link to relevant documentation]. Figure 8 The power grid management platform system receives feedback calls from users within the target distribution area, addressing various opinions and requests. Based on these requests, the system categorizes the calls into different types of work order data. These work order data can include: low voltage feedback work orders, low voltage complaint work orders, power outage complaint work orders, and power outage feedback work orders.

[0118] Based on the type of three-phase load imbalance and the work order data, determining whether to send a risk alarm to the target transformer area includes:

[0119] S810. If the target transformer area receives a low voltage complaint work order on the same day, and the transformer area is a transformer area with severe three-phase load imbalance on the same day, a low voltage complaint risk alarm will be sent to the target transformer area.

[0120] Specifically, if the target distribution area is a distribution area with severe three-phase load imbalance on the day, and the target distribution area receives a call from a user requesting a low voltage complaint, a low voltage complaint risk alarm can be sent to the target distribution area.

[0121] S820. If the target transformer area receives a low voltage complaint work order on the same day, and the transformer area is a transformer area with severe three-phase load imbalance on the same day, a low voltage complaint risk alarm will be sent to the target transformer area.

[0122] Specifically, if the target distribution area is a distribution area with severe three-phase load imbalance on the day, and the target distribution area receives a call from a user requesting low voltage on the same day, a low voltage complaint risk alarm can be sent to the target distribution area.

[0123] S830. If the target distribution area is a distribution area with severe three-phase load imbalance on the day, a low voltage alarm will be sent to the target distribution area.

[0124] Specifically, if the distribution area is only a distribution area with severe three-phase load imbalance on a given day, and no feedback calls have been received from users, a low voltage complaint risk alarm can be sent to the target distribution area.

[0125] S840. If the target transformer area receives a fault outage complaint work order on the same day, the target transformer area is a transformer area with severe three-phase load imbalance on the same day, and the number of fault outage complaint work orders received by the target transformer area in the previous six months is greater than x, then a medium-risk outage complaint alarm is sent to the target transformer area; where x is an integer greater than 4.

[0126] Specifically, if the target distribution area is a distribution area with severe three-phase load imbalance on the current day, and the target distribution area receives a call from a user requesting a power outage complaint on the current day, and the target distribution area has received more than 4 calls from users requesting a power outage complaint in the previous six months, a low voltage complaint risk alarm can be sent to the target distribution area.

[0127] S850. If the target distribution area is a severely unbalanced three-phase load distribution area on the current day, and the number of outage feedback work orders received in the previous six months is greater than y, then a medium-risk outage problem alarm will be sent to the target distribution area; where y is an integer greater than 1.

[0128] Specifically, if the target distribution area is a severely unbalanced three-phase load area on the current day, and the target distribution area has received more than one user complaint call in the six months prior to the current month regarding a power outage, a medium-risk power outage alarm can be sent to the target distribution area.

[0129] S860. If the target transformer area receives a fault outage complaint work order on the same day, and the target transformer area is a daily serious three-phase load imbalance transformer area and a monthly serious three-phase load imbalance transformer area, and the number of fault outage complaint work orders received by the target transformer area in the six months prior to the current month is greater than z, then a high-risk outage complaint alarm will be sent to the target transformer area; where z is an integer greater than 9.

[0130] Specifically, if the target distribution area is a severely unbalanced three-phase load area on a given day and for a given month, and if the target distribution area receives a call from a user requesting a power outage complaint on that day, and has received more than nine such calls in the past six months, a high-risk power outage complaint alarm can be sent to the target distribution area. In other implementations, a high-risk power outage complaint alarm can be sent to the target distribution area if there is an overloaded low-voltage outgoing line in the target area.

[0131] S870. If the target distribution area is a daily severe three-phase load imbalance distribution area and a monthly severe three-phase load imbalance distribution area, a high-risk power outage alarm will be sent to the target distribution area.

[0132] Specifically, if the target distribution area is a severely unbalanced three-phase load area on the current day and also a severely unbalanced three-phase load area for the current month, but no feedback calls are received from users, a high-risk power outage alarm can be sent to the target distribution area.

[0133] In addition, if the target distribution area is a severely unbalanced three-phase load area in the current month, a monthly overload alarm can be sent to the target distribution area. If the target distribution area is a severely unbalanced three-phase load area for three consecutive months or more, a continuous monthly overload alarm can be sent to the target distribution area.

[0134] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and no limitation is imposed herein.

[0135] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method of monitoring and alerting for three-phase load imbalance, characterized by, The method comprises the following steps: Obtaining current data, power data and appeal work order data of a target substation at multiple sampling time points; Determining a three-phase load imbalance type of the target substation according to the current data and the power data; the three-phase load imbalance type comprises a daily general three-phase load imbalance substation, a daily serious three-phase load imbalance substation, a monthly general three-phase load imbalance substation and a monthly serious three-phase load imbalance substation; Determining whether to send a risk warning to the target substation according to the three-phase load imbalance type and the appeal work order data; Determining the three-phase load imbalance type of the target substation according to the current data and the power data comprises: determining a daily maximum load rate and a three-phase imbalance degree of multiple outgoing lines in the target substation according to the current data, and a peak time corresponding to the daily maximum load rate of the outgoing line; Screening a target outgoing line according to the relationship between the daily maximum load rate and a load rate threshold value; Determining the three-phase load imbalance type of the target outgoing line according to the three-phase imbalance degrees of m sampling points before and after the peak time; wherein m is an integer greater than 8.

2. The method of monitoring and alerting for three-phase load imbalance of claim 1, wherein, Determining the three-phase load imbalance type of the target substation according to the current data and the power data comprises: Determining a load rate and a three-phase imbalance degree of the target substation according to the current data and the power data; Determining the three-phase load imbalance type of the target substation according to the load rate, the three-phase imbalance degree and a connection type of a distribution transformer in the target substation.

3. The method of monitoring and alerting for three-phase load imbalance of claim 2, wherein, The calculation formula of the load rate is: ； The calculation formula of the three-phase imbalance degree is: ； Wherein, P is the load rate, I0 is the peak current of the secondary side of the distribution transformer in the target substation, CT is the ratio of the phase current of the primary side of the distribution transformer to the phase current of the secondary side, W is the apparent power of the distribution transformer, ε is the three-phase imbalance degree of the distribution transformer, I1 is the minimum phase current of the secondary side of the distribution transformer, and I2 is the maximum phase current of the secondary side of the distribution transformer.

4. The method of monitoring and alerting for three-phase load imbalance of claim 2, wherein, The connection type of the distribution transformer is Yyn0, and determining the three-phase load imbalance type of the target substation according to the load rate, the three-phase imbalance degree and the connection type of the distribution transformer in the target substation comprises: If the load rate at the continuous n sampling time points is greater than the first load threshold value, and the three-phase imbalance degree is greater than the first imbalance threshold value, it is determined that the target substation is a daily serious three-phase load imbalance substation on the day; wherein n is an integer greater than 5; If the load rate at the continuous n sampling time points is greater than the second load threshold value, the three-phase imbalance degree is greater than the second imbalance threshold value, and the target substation is not a daily serious three-phase load imbalance substation, it is determined that the target substation is a daily general three-phase load imbalance substation on the day.

5. The method of monitoring and alerting for three-phase load imbalance of claim 2, wherein, The connection type of the distribution transformer is Dyn11, and determining the three-phase load imbalance type of the target substation according to the load rate, the three-phase imbalance degree and the connection type of the distribution transformer in the target substation comprises: If the load rate at the sampling time for n consecutive times is greater than the first load threshold, and the three-phase imbalance degree is greater than the third imbalance threshold, it is determined that the target area is a daily serious three-phase load imbalance area; wherein n is an integer greater than 5; If the load rate at the sampling time for n consecutive times is greater than the first load threshold, the three-phase imbalance degree is greater than the first imbalance threshold, and the target area is not a daily serious three-phase load imbalance area, it is determined that the target area is a daily general three-phase load imbalance area.

6. A method of monitoring and alerting for three-phase load imbalance as claimed in claim 4 or 5, characterised in that, The determination of the three-phase load imbalance type of the target area according to the load rate, the three-phase imbalance degree and the wiring type of the distribution transformer in the target area further comprises: If the number of times that the target area is the daily serious three-phase load imbalance area in a month is greater than the first preset number of times, it is determined that the target area is a monthly serious three-phase load imbalance area in the month; If the number of times that the target area is the daily general three-phase load imbalance area or the daily serious three-phase load imbalance area in a month is greater than the second preset number of times and less than the first preset number of times, it is determined that the target area is a monthly general three-phase load imbalance area; wherein the second preset number of times is less than the first preset number of times.

7. The method of monitoring and alerting for three-phase load imbalance of claim 1, wherein, The calculation formula of the daily maximum load rate is: ； wherein, is the daily maximum load rate, I3is the maximum phase current on the day of the outgoing line, and a is the overcurrent setting value.

8. The method of monitoring and alerting for three-phase load imbalance of claim 1, wherein, According to the three-phase imbalance degree of the m sampling points before and after the peak time, the three-phase load imbalance type of the target outgoing line is determined; wherein m is an integer greater than 8, including: If the three-phase imbalance degree of the m sampling points before and after the peak time of the target outgoing line is greater than the third imbalance threshold, and the daily maximum load rate of the target outgoing line is greater than the first load threshold and less than the second load threshold, it is determined that the target outgoing line is a general three-phase load imbalance outgoing line; If the three-phase imbalance degree of the m sampling points before and after the peak time of the target outgoing line is greater than the third imbalance threshold, and the daily maximum load rate of the target outgoing line is greater than or equal to the second load threshold, it is determined that the target outgoing line is a serious three-phase load imbalance outgoing line.

9. The method of monitoring and alerting for three-phase load imbalance of claim 6, wherein, The appeal work order data includes: low voltage opinion work order, low voltage complaint work order, fault power failure complaint work order and fault power failure opinion work order; according to the three-phase load imbalance type and the appeal work order data, it is determined whether to send a risk alarm to the target area, including: If the target area receives the low voltage complaint work order on the same day, and the area is a daily serious three-phase load imbalance area, a low voltage complaint risk alarm is sent to the target area; If the target area receives the low voltage opinion work order on the same day, and the area is a daily serious three-phase load imbalance area, a low voltage complaint risk alarm is sent to the target area; If the target area is a daily serious three-phase load imbalance area, a low voltage alarm is sent to the target area; If the target transformer substation receives the complaint work order of the power failure on the day, the target transformer substation is a daily serious three-phase load imbalance transformer substation, and the number of times that the target transformer substation receives the complaint work order of the power failure in the past six months is greater than x, a medium risk power failure complaint alarm is sent to the target transformer substation; wherein x is an integer greater than 4; If the target transformer substation is a daily serious three-phase load imbalance transformer substation, and the number of times that the target transformer substation receives the complaint work order of the power failure in the past six months is greater than y, a medium risk power failure problem alarm is sent to the target transformer substation; wherein y is an integer greater than 1; If the target transformer substation receives the complaint work order of the power failure on the day, the target transformer substation is a daily serious three-phase load imbalance transformer substation, the target transformer substation is a monthly serious three-phase load imbalance transformer substation, and the number of times that the target transformer substation receives the complaint work order of the power failure in the past six months is greater than z, a high risk power failure complaint alarm is sent to the target transformer substation; wherein z is an integer greater than 9; If the target transformer substation is a daily serious three-phase load imbalance transformer substation, and the target transformer substation is a monthly serious three-phase load imbalance transformer substation, a high risk power failure problem alarm is sent to the target transformer substation.

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