Monitoring and alarming method for three-phase load imbalance

Abstract

The invention discloses a monitoring and warning method for three-phase load imbalance. The method comprises the following steps: acquiring current data, power data and appeal work order data of a target transformer area at a plurality of sampling moments; determining a three-phase load imbalance type of the target transformer area according to the current data and the power data; and according to the three-phase load imbalance type and the appeal work order data, determining whether to send a risk alarm to the target transformer area. According to the technical scheme provided by the embodiment of the invention, the current data and the power data in the target area at the plurality of sampling moments are acquired, so that the working conditions of the distribution transformer in the target area at the plurality of sampling moments are obtained, and then the three-phase load imbalance type of the target area is determined. And the power supply condition in the target area is more accurately judged by combining the appeal work order data fed back by the actual experience of the user in the target area, and an alarm prompt is given to the target area needing to send the risk alarm, so that the technical effect of improving the management efficiency of the power grid and the satisfaction degree of the user is realized.

Description

Technical Field

[0001] The invention relates to the technical field of power systems, and in particular to a monitoring and alarm method for unbalanced three-phase loads. Background Art

[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 has continued to be intelligent and systematic. At present, the low-voltage data monitoring in the power grid system is often incomplete and untimely, which directly makes it difficult for power grid managers to accurately grasp the operation status of the power grid, thus affecting the stability of the power grid and customer satisfaction. Summary of the invention

[0003] The present invention provides a monitoring and alarm method for three-phase load imbalance, so as to accurately judge the degree of three-phase load imbalance in a substation, make reasonable alarms, and improve the overall operation efficiency of the power grid and customer satisfaction.

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

[0005] Obtain current data, power data and request work order data of the target area at multiple sampling times;

[0006] Determine the three-phase load imbalance type of the target area according to the current data and the power data; the three-phase load imbalance type includes a daily general three-phase load imbalance area, a daily severe three-phase load imbalance area, a monthly general three-phase load imbalance area, and a monthly severe three-phase load imbalance area;

[0007] Determine whether to send a risk warning to the target substation according to the three-phase load imbalance type and the request work order data.

[0008] Optionally, determining the three-phase load imbalance type of the target substation according to the current data and the power data includes:

[0009] Determine the load rate and three-phase imbalance of the target substation according to the current data and the power data;

[0010] The three-phase load imbalance type of the target substation is determined according to the load rate, the three-phase imbalance degree and the connection type of the distribution transformer in the target substation.

[0011] Optionally, the calculation formula of the load rate is:

[0012]

[0013] The calculation formula of the three-phase unbalance is:

[0014]

[0015] Among them, 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 side phase current to the secondary side phase current of the distribution transformer, W is the apparent power of the distribution transformer, ε is the three-phase imbalance of the distribution transformer, I1 is the minimum phase current on the secondary side of the distribution transformer, and I2 is the maximum phase current on the secondary side of the distribution transformer.

[0016] Optionally, the connection type of the distribution transformer is Yyn0, and the three-phase load imbalance type of the target substation is determined according to the load rate, the three-phase imbalance degree and the connection type of the distribution transformer in the target substation, including:

[0017] If the load rate at n consecutive sampling moments is greater than the first load threshold, and the three-phase imbalance is greater than the first imbalance threshold, it is determined that the target area is a serious three-phase load imbalance area on that day; wherein n is an integer greater than 5;

[0018] If the load rate at n consecutive sampling moments is greater than the second load threshold, the three-phase imbalance degree is greater than the second imbalance threshold, and the target substation does not belong to the daily severe three-phase load imbalance substation, then the target substation is determined to be a daily general three-phase load imbalance substation on that day.

[0019] Optionally, 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 includes:

[0020] If the load rate at n consecutive sampling moments is greater than the first load threshold, and the three-phase imbalance is greater than the third imbalance threshold, it is determined that the target area is a serious three-phase load imbalance area on that day; wherein n is an integer greater than 5;

[0021] If the load rate at n consecutive sampling moments is greater than the first load threshold, the three-phase imbalance degree is greater than the first imbalance threshold, and the target substation does not belong to the daily severe three-phase load imbalance substation, then it is determined that the target substation is a daily general three-phase load imbalance substation on that day.

[0022] Optionally, the 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 further includes:

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

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

[0025] Optionally, determining the three-phase load imbalance type of the target substation according to the current data and the power data includes:

[0026] Determine the daily maximum load rate and three-phase imbalance of multiple outgoing lines in the target substation according to the current data, and the peak sampling time corresponding to the daily maximum load rate of the outgoing lines;

[0027] Filter the target line according to the relationship between the daily maximum load rate and the load rate threshold;

[0028] The three-phase load imbalance type of the target outgoing line is determined according to the three-phase imbalance degrees of m sampling points before and after the peak moment; wherein m is an integer greater than 8.

[0029] Optionally, the calculation formula of the daily maximum load rate is:

[0030] P max =I3 / a*100

[0031] Among them, P max is the daily maximum load rate, I3 is the maximum phase current of the outgoing line on that day, and a is the overcurrent setting.

[0032] Optionally, the three-phase load imbalance type of the target outgoing line is determined according to the three-phase imbalance degree of m sampling points before and after the peak moment; wherein m is an integer greater than 8;

[0033] If the three-phase unbalance degrees of the m sampling points before and after the peak moment of the target outgoing line are all greater than the third unbalance 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, then the target outgoing line is determined to be a general three-phase load unbalanced outgoing line;

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

[0035] Optionally, the request work order data includes: a low voltage opinion work order, a low voltage complaint work order, a fault power outage complaint work order and a fault power outage opinion work order; according to the three-phase load imbalance type and the request work order data, determining whether to send a risk alarm to the target substation includes:

[0036] If the target substation receives the low voltage complaint work order on the same day, and the substation is a serious three-phase load imbalance substation on the same day, a low voltage complaint risk alarm is sent to the target substation;

[0037] If the target substation receives the low voltage complaint work order on the same day, and the substation is a serious three-phase load imbalance substation on the same day, a low voltage complaint risk alarm is sent to the target substation;

[0038] If the target area is a serious three-phase load imbalance area on that day, a low voltage alarm is sent to the target area;

[0039] If the target substation receives the fault power outage complaint work order on the same day, the target substation is a daily severe three-phase load imbalance substation, and the number of times the target substation received the fault power outage complaint work order in the six months before the current month is greater than x, then a medium-risk power outage complaint alarm is sent to the target substation; wherein x is an integer greater than 4;

[0040] If the target substation is a severe three-phase load imbalance substation on that day, and the number of fault power outage work orders received in the six months before the current month is greater than y, a medium-risk power outage problem alarm is sent to the target substation; where y is an integer greater than 1;

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

[0042] If the target substation is a daily severe three-phase load imbalance substation on that day and a monthly severe three-phase load imbalance substation on that month, a high-risk power outage problem alarm is sent to the target substation.

[0043] The technical solution provided by the embodiment of the present invention obtains the current data and power data of the target substation at multiple sampling times within a day, thereby obtaining the working conditions of the distribution transformer in the target substation at multiple sampling times on the day, and then determining the type of three-phase load imbalance in the target substation. Combined with the demand work order data fed back by the actual experience of users in the target substation, the power supply status in the target substation can be judged more accurately, and an alarm prompt is issued to the target substation that needs to send a risk alarm, thereby achieving the technical effect of improving the management efficiency of the power grid and user satisfaction.

[0044] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

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

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

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

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

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

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

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

[0053] Figure 8A flow chart of another three-phase load imbalance monitoring and alarm method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0054] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work 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 and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0056] Figure 1 A flowchart of a three-phase load imbalance monitoring and alarm method provided by an embodiment of the present invention. This embodiment can be applied to monitoring the three-phase load imbalance in a distribution network area. The method can be executed by a three-phase load imbalance monitoring device, which can be implemented in the form of hardware and / or software and configured in a power grid management platform system. Figure 1 As shown, the method includes:

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

[0058] Specifically, the target area can be an area where a distribution transformer in the power grid system can be responsible for power supply and distribution. The current data can be the three-phase current at both ends of the primary and secondary sides of the distribution transformer. The power data can be the apparent power of the distribution transformer, and the apparent power and current data of the distribution transformer can be collected and obtained through the metering system within the power company. The demand work order data can be the electricity demand telephone information received from the user feedback in the target area, and the demand work order data can be collected and obtained through the power grid management platform system of the power company. The time interval between the sampling moments is different, and the number of sampling moments of the target area in a day will be different. Multiple sampling moments can be set at equal intervals. Exemplarily, the time interval between each sampling moment can be 15 minutes. Correspondingly, the demand work order data in the target area, as well as the apparent power and current data of the distribution transformer, will be collected every 15 minutes. If the time interval between the sampling moments is too long, the current data obtained at each sampling is greatly affected by the fluctuation of the power grid, which will affect the accuracy of the final judgment result; if the time interval between the sampling moments is too short, the amount of current data obtained is large, which affects the judgment efficiency.

[0059] S120, determining the three-phase load imbalance type of the target substation according to the current data and the power data;

[0060] Specifically, the three-phase load balance type in the power system is one of the important indicators for judging the power quality in a power supply area. The difference in power consumption between users in the target substation, or the difference in power consumption time periods and other power consumption reasons will cause different degrees of three-phase load imbalance in the target substation. In one day, multiple sets of current data will be obtained at multiple sampling times. By calculating and analyzing multiple sets of current data and power data, the working conditions of the distribution transformers in the target substation at multiple sampling times of the day can be obtained, thereby determining the three-phase load imbalance type of the target substation.

[0061] S130: Determine whether to send a risk warning to the target substation according to the three-phase load imbalance type and the requested work order data.

[0062] Specifically, the three-phase load imbalance type objectively reflects the power supply status of the target substation based on the operating data of the power grid in the target substation. The three-phase load imbalance type can be a daily general three-phase load imbalance substation, a daily severe three-phase load imbalance substation, a monthly general three-phase load imbalance substation, and a monthly severe three-phase load imbalance substation. The request work order data reflects the power supply status of the target substation based on the feedback of the actual experience of users in the target substation. Therefore, by combining the operating data of the power grid in the target substation and the feedback of the actual experience of users, it is possible to comprehensively judge whether it is necessary to send a risk alarm to the target substation, thereby improving the management efficiency of the power grid and user satisfaction.

[0063] The technical solution provided by the embodiment of the present invention obtains the current data and power data of the target substation at multiple sampling times, thereby obtaining the working conditions of the distribution transformer in the target substation at multiple sampling times, and then determining the type of three-phase load imbalance in the target substation. Combined with the demand work order data fed back by the actual experience of users in the target substation, the power supply status in the target substation can be judged more accurately, and an alarm prompt can be issued to the target substation to which a risk alarm needs to be sent, thereby achieving the technical effect of improving the management efficiency of the power grid and user satisfaction.

[0064] Optionally, Figure 2 A flow chart of another method for monitoring and alarming three-phase load imbalance provided by an embodiment of the present invention. Figure 2 The method comprises:

[0065] S210, obtaining current data, power data and request work order data of the target area at multiple sampling times;

[0066] S220, determining the load rate and three-phase imbalance of the target substation according to the current data and the power data;

[0067] Specifically, the load rate and three-phase imbalance are two important parameters that reflect the power supply quality of the distribution transformer. The load rate can be the ratio of the load value of the distribution transformer during actual operation to its power; the three-phase imbalance can be the degree of inconsistency in the phases of the three-phase currents on the secondary side. At each sampling moment, a set of current data and power data of the distribution transformer in the target substation can be obtained accordingly, and the load rate and three-phase imbalance of the target substation at each sampling moment can be calculated accordingly based on the current data and power data. The current data may include the peak current on the secondary side of the distribution transformer, and the phase currents of the three phases A, B, and C on the secondary side of the distribution transformer.

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

[0069]

[0070] The three-phase imbalance degree of the target substation at a sampling time can be calculated by formula (2).

[0071]

[0072] Among them, P is the load rate, I0 is the peak current on the secondary side of the distribution transformer in the target substation, CT is the ratio of the primary side phase current to the secondary side phase current of the distribution transformer, W is the apparent power of the distribution transformer, ε is the three-phase imbalance of the distribution transformer, I1 is the minimum phase current among the three phases A, B, and C on the secondary side of the distribution transformer, and I2 is the maximum phase current among the three phases A, B, and C on the secondary side of the distribution transformer.

[0073] S230, determining the three-phase load imbalance type of the target area according to the load rate, the three-phase imbalance degree and the connection type of the distribution transformer in the target area;

[0074] Specifically, the connection types of distribution transformers in different target areas may be different. When determining the three-phase load imbalance type of the target area, different judgment criteria can be set for the target area according to the connection type of the distribution transformer, thereby improving the accuracy of the judgment of the three-phase load imbalance type of the target area. Exemplarily, the connection type of the distribution transformer can be Yyn0 connection or Dyn11 connection. Yyn0 connection means that the primary and secondary sides of the distribution transformer are both star-connected, the neutral point of the secondary side of the distribution transformer has a lead wire, and the phase difference between the primary and secondary sides of the distribution transformer is 0 degrees. Dyn11 connection means that the primary side of the distribution transformer is a triangle connection, the secondary side is a star connection, the neutral point of the secondary side of the distribution transformer has a lead wire, and the phase difference between the primary and secondary sides of the distribution transformer is 30 degrees. The star connection method is to connect the ends of the respective windings of the three phases A, B, and C together to form a common point, namely the neutral point. The triangle connection method is to connect the three phases A, B, and C in sequence end to end, and lead out each connected point as three phase lines.

[0075] S240: Determine whether to send a risk warning to the target substation based on the three-phase load imbalance type and the requested work order data.

[0076] Optionally, Figure 3 A flow chart of another method for monitoring and alarming three-phase load imbalance provided by an embodiment of the present invention. Figure 3 When the distribution transformer is of Yyn0 wiring type, the method includes:

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

[0078] S320, determining the load rate and three-phase imbalance of the target substation according to the current data and the power data;

[0079] S330: If the load rate at n consecutive sampling moments is greater than the first load threshold, and the three-phase imbalance is greater than the first imbalance threshold, it is determined that the target area is a serious three-phase load imbalance area on that day; wherein n is an integer greater than 5;

[0080] Specifically, when the time interval between each sampling moment is 15 minutes, the number of sampling moments of the target substation in one day is 96. Correspondingly, if among the 96 sampling moments, at n consecutive sampling moments, the load rate of the distribution transformer of the Yyn0 connection type is greater than the first load threshold, and the three-phase imbalance is greater than the first imbalance threshold, it can be equivalent to that within 15*n minutes, the load rate of the distribution transformer of the Yyn0 connection type exceeds the first load threshold, and the three-phase imbalance exceeds the first imbalance threshold, so that the distribution transformer can be determined to be the target substation of the Yyn0 connection type, and the day is a severe three-phase load imbalance substation. Exemplarily, 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 the sampling moments.

[0081] S340, if the load rate at n consecutive sampling moments is greater than the second load threshold, the three-phase imbalance is greater than the second imbalance threshold, and the target area does not belong to the daily severe three-phase load imbalance area, then determine that the target area is a daily general three-phase load imbalance area on that day;

[0082] Specifically, when the target substation with a distribution transformer of the Yyn0 connection type does not belong to the daily severe three-phase load unbalanced substation, it is necessary to further determine whether the target substation is a daily general three-phase load unbalanced substation. If, among 96 sampling moments, at n consecutive sampling moments, the load rate of the distribution transformer with the Yyn0 connection type is greater than the second load threshold, and the three-phase imbalance is greater than the second imbalance threshold, it can be equivalent to that within 15*n minutes, the load rate of the distribution transformer with the Yyn0 connection type exceeds the second load threshold, and the three-phase imbalance exceeds the second imbalance threshold, so that the distribution transformer can be determined as the target substation with the Yyn0 connection type, and the day is a daily general three-phase load unbalanced substation. Exemplarily, the second load threshold can be 58%, and the second imbalance threshold can be 13%.

[0083] S350: Determine whether to send a risk warning to the target substation based on the three-phase load imbalance type and the requested work order data.

[0084] Optionally, Figure 4 A flow chart of another method for monitoring and alarming three-phase load imbalance provided by an embodiment of the present invention. Figure 4 When the distribution transformer is of Dyn11 connection type, the method includes:

[0085] S410, obtaining current data, power data and request work order data of the target area at multiple sampling times;

[0086] S420, determining the load rate and three-phase imbalance of the target substation according to the current data and the power data;

[0087] S430, if the load rate at n consecutive sampling moments is greater than the first load threshold, and the three-phase imbalance is greater than the third imbalance threshold, then determine that the target area is a serious three-phase load imbalance area on that day; wherein n is an integer greater than 5;

[0088] Specifically, when the time interval between each sampling moment is 15 minutes, the number of sampling moments of the target substation in one day is 96. Correspondingly, if in 96 sampling moments, at n consecutive sampling moments, the load rate of the distribution transformer of the Dyn11 connection type is greater than the first load threshold, and the three-phase imbalance is greater than the third imbalance threshold, it can be equivalent to that the load rate of the distribution transformer of the Dyn11 connection type exceeds the first load threshold within 15*n minutes, and the three-phase imbalance exceeds the third imbalance threshold, so that the target substation with the distribution transformer of the Dyn11 connection type can be determined as a daily severe three-phase load imbalance substation. Exemplarily, the third imbalance threshold can be 48%.

[0089] S440: If the load rate at n consecutive sampling moments is greater than the first load threshold, the three-phase imbalance is greater than the first imbalance threshold, and the target area does not belong to the daily severe three-phase load imbalance area, then determine that the target area is a daily general three-phase load imbalance area on that day;

[0090] Specifically, when the target substation with a distribution transformer of the Dyn11 connection type does not belong to the daily severe three-phase load imbalance substation, it is necessary to further determine whether the target substation is a daily general three-phase load imbalance substation. If, among 96 sampling moments, at n consecutive sampling moments, the load rate of the distribution transformer of the Dyn11 connection type is greater than the first load threshold, and the three-phase imbalance is greater than the second imbalance threshold, it can be equivalent to that within 15*n minutes, the load rate of the distribution transformer of the Dyn11 connection type exceeds the first load threshold, and the three-phase imbalance exceeds the second imbalance threshold, so that the distribution transformer can be determined as the target substation of the Dyn11 connection type, and the day is a daily general three-phase load imbalance substation.

[0091] S450: Determine whether to send a risk warning to the target substation according to the three-phase load imbalance type and the requested work order data.

[0092] Optionally, Figure 5A flow chart of another method for monitoring and alarming three-phase load imbalance provided by an embodiment of the present invention. Figure 5 After determining the three-phase load imbalance type of the target area according to the load rate, the three-phase imbalance degree and the connection type of the distribution transformer in the target area, the method further includes:

[0093] S510, if the number of times that the target area is a daily severe three-phase load unbalanced area in a month is greater than a first preset number, then determining that the target area is a monthly severe three-phase load unbalanced area in that month;

[0094] Specifically, within the target area, statistics are collected starting from the beginning of each natural month. If the number of times that the target area is determined to be a daily severe three-phase load imbalance area in that month exceeds a first preset number, it can be determined that the target area is a monthly severe three-phase load imbalance area in that month. For example, the first preset number can be 10.

[0095] S520. If the number of times that the target substation is a daily general three-phase load unbalanced substation or a daily severe three-phase load unbalanced substation within a month is greater than the second preset number and less than the first preset number, then it is determined that the target substation is a monthly general three-phase load unbalanced substation in that month; wherein the second preset number is less than the first preset number.

[0096] Specifically, before the target substation is confirmed as a monthly severe three-phase load unbalanced substation, it is necessary to determine whether the target substation belongs to a monthly general three-phase load unbalanced substation in the current month. Exemplarily, the first preset number may be 10, and the second preset number may be 8. In the target substation, statistics are started from the beginning of each natural month. If the total number of times the target substation is determined to be a daily general three-phase load unbalanced substation or a daily severe three-phase load unbalanced substation in a month exceeds 8 times and is less than 10 times, it can be determined that the target substation is a monthly general three-phase load unbalanced substation in the current month.

[0097] Optionally, Figure 6 A flow chart of another method for monitoring and alarming three-phase load imbalance provided by an embodiment of the present invention. Figure 6 The method comprises:

[0098] S610, obtaining current data, power data and request work order data of the target area at multiple sampling times;

[0099] S620, determining the daily maximum load rate and three-phase imbalance of multiple outgoing lines in the target substation according to the current data, and the peak sampling time corresponding to the daily maximum load rate of the outgoing lines;

[0100] Specifically, the outgoing line may be a subordinate branch area within the target substation. Correspondingly, the acquired current data may be the phase currents of the three phases A, B, and C on the load side of the outgoing line. The daily maximum load rate of the outgoing line may be calculated by formula (3).

[0101] P max =I3 / a*100 (3)

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

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

[0104]

[0105] Among them, 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 outgoing line load side, and I5 is the maximum phase current among the three phases A, B, and C on the outgoing line load side.

[0106] S630, selecting target outgoing lines according to the relationship between the daily maximum load rate and the load rate threshold;

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

[0108] S640. Determine the three-phase load imbalance type of the target outgoing line according to the three-phase imbalance degree of m sampling points before and after the peak moment; wherein m is an integer greater than 8.

[0109] Specifically, after the target outgoing line of the corresponding type is screened, it can be determined whether the target outgoing line belongs to the corresponding type of three-phase load unbalanced outgoing line according to the three-phase unbalance degree of m sampling points before and after the outgoing line peak moment.

[0110] Optionally, Figure 7 A flow chart of another method for monitoring and alarming three-phase load imbalance provided by an embodiment of the present invention. Figure 7 The method comprises:

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

[0112] S720, determining the daily maximum load rate and three-phase imbalance of multiple outgoing lines in the target substation according to the current data, and the peak sampling time corresponding to the daily maximum load rate of the outgoing lines;

[0113] S730: If the three-phase unbalance degrees of the m sampling points before and after the peak moment of the target outgoing line are all greater than the third unbalance 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, the target outgoing line is determined to be a general three-phase load unbalanced outgoing line;

[0114] Specifically, if the maximum load rate of the m sampling points before and after the peak moment of the outgoing line is greater than the first load threshold and less than the second load threshold, the outgoing line can be judged to be a general three-phase load unbalanced target outgoing line. Further, if the three-phase imbalance of the m sampling points before and after the peak moment of the general three-phase load unbalanced target outgoing line is greater than the third imbalance threshold, the general three-phase load unbalanced target outgoing line can be determined to be a general three-phase load unbalanced outgoing line. Exemplarily, 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 and set according to the actual working conditions corresponding to the outgoing line.

[0115] S740: If the three-phase imbalance of the m sampling points before and after the peak moment 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, the target outgoing line is determined to be a severe three-phase load imbalance outgoing line.

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

[0117] Optionally, Figure 8 A flow chart of another method for monitoring and alarming three-phase load imbalance provided by an embodiment of the present invention. Figure 8 The power grid management platform system will receive feedback calls from users in the target substation area with different opinions and demands. According to the users' opinions and demands, the feedback calls can be classified to obtain various demand work order data. The demand work order data may include: low voltage opinion work order, low voltage complaint work order, fault power outage complaint work order and fault power outage opinion work order.

[0118] According to the three-phase load imbalance type and the request work order data, determine whether to send a risk alarm to the target area, including:

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

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

[0121] S820: If the target substation receives a low voltage complaint work order on the day, and the substation is a serious three-phase load imbalance substation on the day, a low voltage complaint risk alarm is sent to the target substation;

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

[0123] S830, if the target area is a serious three-phase load imbalance area on that day, a low voltage alarm is sent to the target area;

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

[0125] S840, if the target substation receives a fault power outage complaint work order on the current day, the target substation is a daily severe three-phase load imbalance substation, and the number of fault power outage complaint work orders received by the target substation in the six months before the current month is greater than x, then a medium-risk power outage complaint alarm is sent to the target substation; where x is an integer greater than 4;

[0126] Specifically, if the target substation is a substation with severe three-phase load imbalance on the day, the target substation receives a phone call from a user complaining about a power outage due to a fault on the day, and the target substation received more than four phone calls from users complaining about a power outage due to a fault in the six months before the current month, a low voltage complaint risk alert can be sent to the target substation.

[0127] S850. If the target substation is a daily severe three-phase load imbalance substation on that day, and the number of fault power outage work orders received in the six months before that month is greater than y, a medium-risk power outage problem alarm is sent to the target substation; where y is an integer greater than 1;

[0128] Specifically, if the target substation is a substation with severe three-phase load imbalance on that day, and the target substation received more than one user complaint call for fault power outage work order in the six months before that month, a medium-risk power outage problem alarm can be sent to the target substation.

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

[0130] Specifically, if the target substation is a daily severe three-phase load imbalance substation on the current day, a monthly severe three-phase load imbalance substation on the current month, and the target substation receives a call from a user with a fault power outage complaint work order on the current day, and the target substation has received more than 9 calls from users with a fault power outage complaint work order in the past six months, a high-risk power outage complaint alarm can be sent to the target substation. In other implementations, a high-risk power outage complaint alarm can be sent to the target substation if there is an overloaded low-voltage outlet in the target area.

[0131] S870: If the target substation has a daily severe three-phase load imbalance on that day and a monthly severe three-phase load imbalance on that month, a high-risk power outage alarm is sent to the target substation.

[0132] Specifically, if the target substation is a daily severe three-phase load imbalance substation on that day and a monthly severe three-phase load imbalance substation on that month, but does not receive any feedback calls from users, a high-risk power outage alarm can be sent to the target substation.

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

[0134] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0135] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A monitoring and alarm method for three-phase load imbalance, characterized in that: include: Obtain current data, power data and request work order data of the target area at multiple sampling times; Determine the three-phase load imbalance type of the target area according to the current data and the power data; the three-phase load imbalance type includes a daily general three-phase load imbalance area, a daily severe three-phase load imbalance area, a monthly general three-phase load imbalance area, and a monthly severe three-phase load imbalance area; Determine whether to send a risk warning to the target substation according to the three-phase load imbalance type and the request work order data.

2. The monitoring and alarming method for three-phase load imbalance according to claim 1 is characterized in that: Determining the three-phase load imbalance type of the target substation according to the current data and the power data includes: Determine the load rate and three-phase imbalance of the target substation according to the current data and the power data; The three-phase load imbalance type of the target substation is determined according to the load rate, the three-phase imbalance degree and the connection type of the distribution transformer in the target substation.

3. The monitoring and alarming method for three-phase load imbalance according to claim 2 is characterized in that: The calculation formula of the load rate is: The calculation formula of the three-phase unbalance is: Among them, 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 side phase current to the secondary side phase current of the distribution transformer, W is the apparent power of the distribution transformer, ε is the three-phase imbalance of the distribution transformer, I1 is the minimum phase current on the secondary side of the distribution transformer, and I2 is the maximum phase current on the secondary side of the distribution transformer.

4. The monitoring and alarming method for three-phase load imbalance according to claim 2 is characterized in that: The connection type of the distribution transformer is Yyn0, and the three-phase load imbalance type of the target substation is determined according to the load rate, the three-phase imbalance degree and the connection type of the distribution transformer in the target substation, including: If the load rate at n consecutive sampling moments is greater than the first load threshold, and the three-phase imbalance is greater than the first imbalance threshold, it is determined that the target area is a serious three-phase load imbalance area on that day; wherein n is an integer greater than 5; If the load rate at n consecutive sampling moments is greater than the second load threshold, the three-phase imbalance degree is greater than the second imbalance threshold, and the target substation does not belong to the daily severe three-phase load imbalance substation, then the target substation is determined to be a daily general three-phase load imbalance substation on that day.

5. The monitoring and alarming method for three-phase load imbalance according to claim 2 is characterized in that: The connection type of the distribution transformer is Dyn11, and the three-phase load imbalance type of the target substation is determined according to the load rate, the three-phase imbalance degree and the connection type of the distribution transformer in the target substation, including: If the load rate at n consecutive sampling moments is greater than the first load threshold, and the three-phase imbalance is greater than the third imbalance threshold, it is determined that the target area is a serious three-phase load imbalance area on that day; wherein n is an integer greater than 5; If the load rate at n consecutive sampling moments is greater than the first load threshold, the three-phase imbalance degree is greater than the first imbalance threshold, and the target substation does not belong to the daily severe three-phase load imbalance substation, then the target substation is determined to be a daily general three-phase load imbalance substation on that day.

6. The monitoring and alarming method for three-phase load imbalance according to claim 4 or 5, characterized in that: The method of determining the three-phase load imbalance type of the target area according to the load rate, the three-phase imbalance degree and the connection type of the distribution transformer in the target area further includes: If the number of times that the target area is the daily severe three-phase load imbalance area in a month is greater than a first preset number, then the target area is determined to be the monthly severe three-phase load imbalance area in that month; If the number of times that the target substation is the daily general three-phase load unbalanced substation or the daily severe three-phase load unbalanced substation within a month is greater than the second preset number and less than the first preset number, then it is determined that the target substation is the monthly general three-phase load unbalanced substation for the current month; wherein the second preset number is less than the first preset number.

7. The monitoring and alarming method for three-phase load imbalance according to claim 1 is characterized in that: Determining the three-phase load imbalance type of the target substation according to the current data and the power data includes: Determine the daily maximum load rate and three-phase imbalance of multiple outgoing lines in the target substation according to the current data, and the peak sampling time corresponding to the daily maximum load rate of the outgoing lines; Filter the target line according to the relationship between the daily maximum load rate and the load rate threshold; The three-phase load imbalance type of the target outgoing line is determined according to the three-phase imbalance degrees of m sampling points before and after the peak moment; wherein m is an integer greater than 8.

8. The monitoring and alarming method for three-phase load imbalance according to claim 7 is characterized in that: The calculation formula of the daily maximum load rate is: P max =I3 / a*100 Among them, P max is the daily maximum load rate, I3 is the maximum phase current of the outgoing line on that day, and a is the overcurrent setting.

9. The monitoring and alarming method for three-phase load imbalance according to claim 7, characterized in that: Determine the three-phase load imbalance type of the target outgoing line according to the three-phase imbalance degree of m sampling points before and after the peak moment; wherein m is an integer greater than 8, including: If the three-phase unbalance degrees of the m sampling points before and after the peak moment of the target outgoing line are all greater than the third unbalance 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, then the target outgoing line is determined to be a general three-phase load unbalanced outgoing line; If the three-phase imbalance degrees of the m sampling points before and after the peak moment of the target outlet are all greater than the third imbalance threshold, and the daily maximum load rate of the target outlet is greater than or equal to the second load threshold, the target outlet is determined to be a severe three-phase load imbalance outlet.

10. The monitoring and alarming method for three-phase load imbalance according to claim 6, characterized in that: The request work order data includes: low voltage opinion work order, low voltage complaint work order, fault power outage complaint work order and fault power outage opinion work order; according to the three-phase load imbalance type and the request work order data, determining whether to send a risk alarm to the target substation includes: If the target substation receives the low voltage complaint work order on the same day, and the substation is a serious three-phase load imbalance substation on the same day, a low voltage complaint risk alarm is sent to the target substation; If the target substation receives the low voltage complaint work order on the same day, and the substation is a serious three-phase load imbalance substation on the same day, a low voltage complaint risk alarm is sent to the target substation; If the target area is a serious three-phase load imbalance area on that day, a low voltage alarm is sent to the target area; If the target substation receives the fault power outage complaint work order on the same day, the target substation is a daily severe three-phase load imbalance substation, and the number of times the target substation received the fault power outage complaint work order in the six months before the current month is greater than x, then a medium-risk power outage complaint alarm is sent to the target substation; wherein x is an integer greater than 4; If the target substation is a severe three-phase load imbalance substation on that day, and the number of fault power outage work orders received in the six months before the current month is greater than y, a medium-risk power outage problem alarm is sent to the target substation; where y is an integer greater than 1; If the target substation receives a fault power outage complaint work order on the same day, the same day is a daily severe three-phase load imbalance substation, the same month is a monthly severe three-phase load imbalance substation, and the number of fault power outage complaint work orders received by the target substation in the six months before the current month is greater than z, then a high-risk power outage complaint alarm is sent to the target substation; wherein z is an integer greater than 9; If the target substation is a daily severe three-phase load imbalance substation on that day and a monthly severe three-phase load imbalance substation on that month, a high-risk power outage problem alarm is sent to the target substation.

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