CN110137947B - Grid voltage sag severity assessment method based on ITIC curve - Google Patents
Grid voltage sag severity assessment method based on ITIC curve Download PDFInfo
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Abstract
The invention discloses a grid voltage sag severity assessment method based on an ITIC curve, which comprises the following steps of: s1, acquiring related data of a grid voltage sag event, and preprocessing the data; s2, dividing the voltage sag event into three types according to the duration time of the voltage sag event; s3, counting the duty ratio of all the voltage sag events in the region, and obtaining the fraction of the duty ratio according to a duty ratio scoring table; s4, counting the average voltage sag depth of the voltage sag event, and judging the obtained fraction of the average voltage sag depth of each region; and S5, carrying out weighted average on the score of the duty ratio of the step S3 and the average voltage sag depth of the step S4 to obtain a comprehensive score of the voltage sag severity of a certain region, and obtaining the severity level of the region according to the comprehensive score. The invention not only avoids the defect that a single evaluation index contains limited information quantity, but also considers the influence of different types of voltage sag events on sensitive equipment.
Description
Technical Field
The invention relates to the technical field of electric energy quality analysis, in particular to a grid voltage sag severity assessment method based on an ITIC curve.
Background
With the development of telecommunication engineering technology, computer application technology, power electronics technology and other industries, the proportion of sensitive load in the total load of a power system is increased year by year, and the problem of voltage sag is gaining importance in the problem of power quality of a plurality of people. The voltage sag refers to the condition that a certain point in the power system is subjected to low voltage for 10 ms-1 min for short duration and then is recovered to normal voltage under the power frequency condition, and the average root value of the voltage in the process is in the range of 0.1 p.u-0.9 p.u according to the definition of Institute of Electrical and Electronics Engineers (IEEE). When voltage sag occurs, a motor on a production line may be stopped, a Programmable Logic Controller (PLC) may malfunction, computer stored data may be lost and the like, and the transient power quality problem may cause serious threat to personal safety and serious loss to national economy. According to the relevant statistical investigation, of all the electric energy quality complaints, more than nine are caused by voltage sag, and the voltage sag problem is increasingly attracting attention of the power supply community. The voltage sag monitoring device is arranged at an important load point, the power grid voltage sag data are collected, the power grid voltage sag severity is evaluated in a grade mode, and the method has extremely important significance for operation of a power system and management of electric energy quality.
Voltage sag, an inevitable natural phenomenon, can be solved or alleviated by enhancing the immunity of the voltage sag of the equipment and reducing the chance of the equipment suffering from the voltage sag, which needs to be solved by the cooperation of the power department, the user and the equipment manufacturer. To reduce the negative impact of voltage sag on the user device, ITIC curves and SEMI F47 curves are presented sequentially to guide device manufacturers to design electrical devices that conform to the voltage sag sensitive lines, enhancing the device's tolerance to voltage sag. However, in China, the research on voltage sag starts, and more of the problem of voltage sag is from the user perspective, and the influence of the voltage sag at a certain monitoring point on user equipment is mostly measured according to the characteristics of the monitored voltage sag event such as the sag amplitude, duration, occurrence frequency and the like. The indexes of measuring the damage condition of the user at the load angle, such as the index of the change rate of the average effective value of the system voltage, the index of the event of the average sag number of the user and the like, are more popular at present, but less from the power grid management angle, a reasonable judging mechanism is provided on the basis of comprehensively considering the influence of the event of the voltage sag on the power quality of the power grid in a certain area, and detailed information of the system voltage sag in the area and corresponding voltage sag severity ratings are provided for the user. Therefore, the voltage sag data are necessary to be deeply mined and subjected to mathematical modeling analysis by combining a big data analysis means, and the severity of the voltage sag event of the regional power grid is subjected to grade assessment, so that system voltage sag information is provided for users, plant addresses and equipment selection of the users are facilitated, and a foundation is laid for power quality management work.
Disclosure of Invention
The invention aims to provide a voltage sag severity grading method from the perspective of power grid management, and solves the problems of inaccurate evaluation of the voltage sag severity and unreasonable grading of the severity in the prior art.
The technical scheme adopted by the invention is as follows.
An ITIC curve-based power grid voltage sag severity assessment method comprises the following steps:
s1, acquiring related data of a grid voltage sag event, and preprocessing the data;
s2, dividing the voltage sag event into three types according to the duration time of the voltage sag event, wherein the voltage sag event is a first type voltage sag event, a second type voltage sag event and a third type voltage sag event;
s3, counting the duty ratio of all voltage sag events in a non-damaged area of ITIC curve equipment, namely the voltage sag event in the area by combining with an ITIC curve, and calculating the fraction obtained by the duty ratio; the non-damage area of the ITIC curve equipment is an area surrounded by a TIC curve and a duration coordinate axis;
s4, counting the average voltage sag depth of all voltage sag events in the non-damaged areas of the ITIC curve equipment in the area, and judging the fraction of the average voltage sag depth of each area by using an average voltage sag depth scoring table;
s5, taking a weighted average value through the obtained fraction of the average voltage sag depth of the region and the obtained fraction of the voltage sag event ratio of the non-damaged region of the equipment to obtain a comprehensive score of the severity of the voltage sag of a certain region, obtaining the severity level corresponding to the region according to the comprehensive score, wherein the higher the fraction is, the lighter the severity of the voltage sag of the region is represented, and the power quality management mode of the region can not be changed; the lower the score, the more serious the voltage sag degree of the region is, the importance should be attached to the power system manager, the common cause of the voltage sag is found, and the power quality management method is improved in a targeted manner.
Further, the data in step S1 includes the occurrence time, duration, depth of dip and monitoring node of the voltage dip.
Furthermore, besides normal data, there are two abnormal data in the dip data recorded by the city monitoring system: firstly, monitoring that the voltage sag duration time of the node is a certain fixed value due to equipment failure; secondly, because the power failure is planned, the time length exceeds the timing limit of the monitoring equipment, the statistics of the system voltage sag times is affected when the data record is wrong, in addition, because the monitored sag wave is changed greatly, the monitoring system takes the same sag as different sag events, and the abnormal data are removed for accurately analyzing the result, so the preprocessing in the step S1 comprises the following steps:
1) Removing abnormal data caused by abnormal operation of the monitoring equipment and the power quality monitoring system;
2) Judging the voltage sag event with the occurrence time interval not exceeding 60s as repeated data and only preserving one item;
3) Voltage dip events with durations exceeding 5000ms are rejected.
Further, the type of voltage sag event in step S2 is determined as follows:
0≤T x ＜20 (1)
20≤T x ＜500 (2)
500≤T x ＜5000 (3)
wherein T is x For the duration of the event x extraction, x=1, 2,3 … …, n, n is the total number of dip events in ms. According to the ITIC curve, if the formula (1) is satisfied, the voltage sag event is a first-type voltage sag event, wherein the voltage sag depth of the first-type voltage sag event is a reference value V ref 0%; if the formula (2) is satisfied, the voltage sag event is a second-class voltage sag event, wherein the voltage sag depth of the second-class voltage sag event is a reference value V ref 70%; if the formula (3) is satisfied, the voltage sag event is a third type of voltage sag event, wherein the voltage sag depth of the third type of voltage sag event is a reference value V ref 80%.
Further, the statistical manner of step S3 is as follows:
wherein N is j M is the number of voltage sag events in the jth region of the non-damaged region of the ITIC curve equipment j For the total number of voltage sag events in the jth region, P j Event of voltage sag for non-damaged area of equipmentThe duty cycle of all voltage sag events in the region.
Further, the fraction obtained by the duty cycle is calculated as follows:
G 1 ＝(1-P j )×100
wherein G is 1 Fractional, P, fraction of the voltage sag event duty cycle for the non-damaged area of the regional equipment j Voltage sag events for a device no damage zone the duty cycle of all voltage sag events in that zone.
For the jth zone, the higher the fraction obtained, the smaller the transient event fraction for all events representing a non-damaged area of the ITIC curve device.
Further, the average voltage dip depth scoring table is a scoring table obtained by an expert scoring method, wherein the average voltage dip depth is divided into a plurality of different scores according to the numerical value according to expert experience, and the higher the score is, the lower the average voltage dip depth in the region is.
Further, the average voltage sag depth in the step S4 is based on the ITIC curve, the voltage sag depth of each voltage sag event relative to the ITIC curve is counted, and the counted voltage sag depths are added and averaged to obtain the average voltage sag depth of the region;
specifically, the voltage dip depth of the voltage dip event relative to the ITIC curve is:
V i ＝V x -V ref
wherein V is x The voltage sag depth of the xth voltage sag event in the data preprocessed in the step S1 is V ref The reference value of the voltage sag depth is the voltage sag event x belonging to the category.
The average voltage dip depth in the region is calculated by adopting the formula (4):
wherein L is j Represents the average voltage sag depth of the jth region, N is the total voltage sag event of the regionThe number n is the number of voltage sag events in the region, V i Is the voltage dip depth of the ith voltage dip event relative to the ITIC curve.
For the jth zone, the value of the average voltage dip depth determines the fraction of the average voltage dip depth for that zone. The higher the score obtained, the lower the average voltage dip depth in the region.
Furthermore, the weighted average value is obtained through the average voltage sag depth of the region and the voltage sag event proportion of the non-damaged region of the equipment, so that the equipment side voltage sag immunity is fully considered, and the power quality management method suggestion is provided for the power system manager from the network side information.
Further, the average voltage sag depth is used for evaluating the severity of the voltage sag of the regional power grid, the sag depth of the voltage sag event of the region is judged by combining with an ITIC curve, and a powerful reference is provided for the management mode of the power system manager in an expert scoring mode.
Furthermore, the immunity of the sensitive load in the power grid to the voltage sag of the power grid is fully considered by combining the information of the network side and the equipment side, the influence range of the voltage sag event in the region on the sensitive load is preliminarily determined on the basis of an ITIC curve, and the severity of the voltage sag in the region is estimated from the angle of user equipment through an expert scoring form.
Further, a weighted average is obtained through the average voltage sag depth of the area and the fraction obtained by the voltage sag event proportion of the equipment non-damaged area, the comprehensive score of the voltage sag severity of a certain area is obtained, and the corresponding severity level is obtained;
the calculation formula of the composite score is as follows:
G＝ω 1 ·G 1 +ω 2 ·G 2 (5)
wherein G is the comprehensive score of the severity of the voltage sag in the region, G 1 Fractional, G, of the duty cycle of the voltage sag event in the non-damaged area of the device 2 The fraction, ω, of the average voltage dip depth for that region 1 And omega 2 G in the comprehensive score of the severity of the voltage sag 1 And G 2 Is a weight of (a).
As shown in table H, the higher the score of the composite score, the lower the voltage sag severity level, which represents that the lower the voltage sag severity level in the region, the power quality management mode of the region with the first and second voltage sag severity levels can not be changed, and the region with the third voltage sag severity level needs to be adjusted based on the power quality management mode of the region; the lower the fraction, the higher the voltage sag severity level, which represents that the voltage sag severity of the region is serious, and the electric energy quality problem of the region with the corresponding voltage sag severity of four and five levels should be considered as the attention of an electric power system manager, so as to find the common cause of the voltage sag and improve the electric energy quality management method in a targeted manner.
Table H voltage sag severity grading
Compared with the prior art, the invention has the beneficial effects that:
(1) The evaluation method combines the characteristics of the voltage tolerance curve of the equipment, and fully considers the voltage sag multi-characteristic quantity, including sag depth, duration time and the like.
(2) For sensitive equipment, the severity of the voltage sag in the area is measured through the out-of-limit degree of the ITIC curve and the average voltage sag depth, so that the defect that a single evaluation index contains limited information is avoided, and the influence of different types of voltage sag events on the sensitive equipment is considered.
Drawings
FIG. 1 is a flowchart of an average Euclidean distance calculation;
FIG. 2 is a schematic diagram of the various operating regions of the ITIC curve;
FIG. 3 is a flow chart of a grid voltage sag severity assessment method based on ITIC curves.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail with reference to the accompanying drawings.
An electrical network voltage sag severity assessment method based on ITIC curves as shown in fig. 1 and 3 comprises the following steps:
s1, acquiring data related to a voltage sag event of a power grid, including but not limited to information such as occurrence time, duration time, sag depth, monitoring nodes and the like of the voltage sag, and preprocessing transient data.
In consideration of malfunction of monitoring equipment and a power quality monitoring system, abnormal data are removed in the embodiment, and voltage sag events with the occurrence time interval not exceeding 60s are judged to be repeated data and only one item is reserved. Since the voltage dip only lasts for 10 ms-1 min, considering that the monitoring instrument accuracy is certain, transient data with a duration exceeding 5000ms are rejected in this embodiment.
In this example, 2017 voltage sag data from 6 regions of a city is collected, and 1409 voltage sag data are collected. After eliminating abnormal data and transient data with duration exceeding 5000ms, 1231 voltage sag data which participate in the evaluation of the severity degree of the voltage sag of the power grid are added. The total number of sag events and the number of out-of-limit sag events corresponding to each region are shown in table 1.
Table 1 list of event counts for each region
S2, judging the category to which the voltage sag event belongs.
The method mainly comprises the steps of dividing voltage sag events into two types according to the duration of the voltage sag events based on an ITIC curve, wherein the voltage sag depth reference value of the first type of voltage sag event is 0%; the voltage sag depth reference value of the second type of voltage sag event is 70%; the voltage sag depth reference for the third class of voltage sag events is 80%.
The type criteria of the voltage sag event are as follows:
0≤T x ＜20 (1)
20≤T x ＜500 (2)
500≤T x ＜5000 (3)
wherein T is x For the duration of the event x extraction, x=1, 2,3 … …, n (n is the total number of dip events), in ms. According to the ITIC curve, if the formula (1) is satisfied, the voltage sag event is a first-type voltage sag event, wherein the voltage sag depth of the first-type voltage sag event is a reference value V ref 0%; if the formula (2) is satisfied, the voltage sag event is a second-class voltage sag event, wherein the voltage sag depth of the second-class voltage sag event is a reference value V ref 70%; if the formula (3) is satisfied, the voltage sag event is a third type of voltage sag event, wherein the voltage sag depth of the third type of voltage sag event is a reference value V ref 80%.
S3, counting the proportion of voltage sag events in a non-damaged area (namely the lower part of a voltage tolerance curve) of the ITIC curve equipment in all voltage sag events in the area by combining with the ITIC curve. Judging the grades of the voltage sag event proportion of the equipment non-damaged area in each area by using a voltage sag event proportion evaluation table, wherein each grade corresponds to a score, and the higher the obtained score is, the smaller the proportion of the voltage sag event proportion of the equipment non-damaged area in the ITIC curve equipment is.
As shown in fig. 2, the area surrounded by the ITIC curve and the duration coordinate axis is the non-damaged area of the ITIC curve equipment, and the part outside the ITIC curve is the normal operation area. For most devices, normal function of the device will not be guaranteed in the non-damaged area of the ITIC curve device, but will not cause damage to the device itself. The ITIC curve has turns at the time durations of 20ms and 500ms, and the dip depth reference value is 0% for the time duration within the range of 0-20 ms; the reference value of the dip depth is 70% in the range of 20-500 ms, and 80% in the range of 500-5000 ms.
Specifically, the voltage sag event duty ratio P of the equipment non-damaged area is obtained j The following are provided:
wherein N is j M is the number of voltage sag events in the non-damaged area of ITIC curve equipment in all sag events in the jth area j For the total number of voltage sag events in the jth region, P j Voltage sag events for a device no damage zone the duty cycle of all voltage sag events in that zone.
The calculated fraction is as follows:
G 1 ＝(1-P j )×100
wherein G is 1 Fractional, P, fraction of the voltage sag event duty cycle for the device no damage region j Voltage sag events for a device no damage zone the duty cycle of all voltage sag events in that zone.
In this embodiment, the statistical results and the corresponding scores are shown in the following table:
table 2 example of the duty ratio score table
And S4, counting the average voltage sag depth of all voltage sag events of the region, which are positioned in the non-damaged region (namely the lower part of the voltage tolerance curve) of the ITIC curve equipment, and judging the obtained fraction of the average voltage sag depth of each region by using an average voltage sag depth scoring table.
The relative voltage dip depth for voltage dip event x is:
V i ＝V x -V ref
wherein V is x The voltage sag depth is the voltage sag event x, x is 1-1231, V ref The reference value of the voltage sag depth is the voltage sag event x belonging to the category.
The average voltage sag depth is obtained by taking an ITIC curve as a reference, counting the voltage sag depth of each voltage sag event relative to the ITIC curve, adding and averaging the voltage sag depths to obtain the average voltage sag depth of the region, and the calculation formula is as follows:
wherein L is j Represents the average voltage sag depth of the jth region, N is the total number of voltage sag events of the region, N is the number of voltage sag events of the region, V i Is the voltage dip depth of the ith voltage dip event relative to the ITIC curve.
The average voltage dip depth scoring table is shown in table 3, which is obtained by expert scoring, and the average voltage dip depth is divided into a plurality of different scores according to the numerical value according to expert experience. For the jth zone, the value of the average voltage dip depth determines the fraction of the average voltage dip depth for that zone. The higher the fraction of average voltage dip depth, the lower the average voltage dip depth for that region.
Table 3 average voltage dip depth scoring table
In this embodiment, the average voltage dip depth score table is as follows, based on expert experience:
table 4 example average voltage dip depth calculation and scoring results
And S5, taking a weighted average of the fraction obtained in the step S3 and the average voltage sag depth in the step S4 to obtain a comprehensive score of the voltage sag severity of a certain region, and obtaining the severity level corresponding to the region, wherein a calculation formula is shown in (5).
G＝ω 1 ·G 1 +ω 2 ·G 2 (5)
Wherein G is the comprehensive score of the severity of the voltage sag in the region, G 1 Fractional, G, of the duty cycle of the voltage sag event in the non-damaged area of the device 2 The fraction, ω, of the average voltage dip depth for that region 1 And omega 2 G in the comprehensive score of the severity of the voltage sag 1 And G 2 Is a weight of (a).
As shown in table 5, the higher the comprehensive score, the lower the voltage sag severity level, which represents the lighter the voltage sag severity in the region, the power quality management mode of the region with the first and second voltage sag severity levels can not be changed, and the region with the third voltage sag severity level needs to be adjusted based on the power quality management mode of the region; the lower the fraction of the average voltage sag depth is, the higher the voltage sag severity level is, which represents that the voltage sag degree of the region is serious, and the electric energy quality problem of the region with the corresponding voltage sag severity of four and five levels should be regarded as the importance of an electric power system manager, so as to find the common cause of the voltage sag and improve the electric energy quality management method in a targeted manner.
TABLE 5 voltage sag severity grading
In the present embodiment, let ω 1 ＝ω 2 =0.5, the calculation result is shown in table 6.
Table 6 example comprehensive scoring table for severity of voltage dip
According to the comprehensive scoring result, the quality of the electric energy in each region is compared as follows:
3＞5＞2＞4＞1＞6
wherein, > represents a preference. The power quality is the best in the area 3 and the power quality is the worst in the area 6.
For the area 3, the electric energy quality grade of the area is two-level, so that voltage sag events causing equipment faults are less generated, and the electric energy quality management mode of the area is unchanged; for the areas No. 5, no. 2 and No. 4, the electric energy quality grades of the three areas are four, the electric energy quality is poor, voltage sag events which easily cause equipment faults occur, and the electric energy quality management mode of the current area should be adjusted in a targeted manner based on the analysis of voltage sag causes; for the areas 1 and 6, the electric energy quality grades of the two areas are five, the electric energy quality is poor, voltage sag events which cause equipment faults are easy to occur, the reasons for occurrence of power grid sag should be analyzed seriously, and the electric energy quality management mode of the current area is changed according to common reasons.
The above description is illustrative of the invention and is not intended to limit the scope of the invention, but any modifications, equivalents, improvements, etc. within the spirit and principles of the invention are intended to be included within the scope of the invention.
Claims (9)
1. The grid voltage sag severity assessment method based on the ITIC curve is characterized by comprising the following steps of:
s1, acquiring related data of a grid voltage sag event, and preprocessing the data;
s2, dividing the voltage sag event into three types according to the duration time of the voltage sag event, wherein the voltage sag event is a first type voltage sag event, a second type voltage sag event and a third type voltage sag event;
s3, counting the duty ratio of all voltage sag events in a non-damaged area of ITIC curve equipment, namely the voltage sag event in the area by combining with an ITIC curve, and calculating the fraction obtained by the duty ratio; the non-damage area of the ITIC curve equipment is an area surrounded by ITIC curve and duration coordinate axes;
s4, counting the average voltage sag depth of all voltage sag events in the non-damaged areas of the ITIC curve equipment in the area, and judging the obtained fraction of the average voltage sag depth of each area by using an average voltage sag depth scoring table;
and S5, taking a weighted average of the fraction obtained by the duty ratio of the step S3 and the fraction obtained by the average voltage sag depth of the step S4 to obtain a comprehensive score of the voltage sag severity of a certain region, and obtaining the severity level corresponding to the region according to the comprehensive score.
2. The method of claim 1, wherein the data of step S1 includes time of occurrence, duration, depth of dip and monitoring node of voltage dip.
3. The method for evaluating the severity of a sag of a power grid based on ITIC curves according to claim 1, wherein the preprocessing of step S1 comprises the steps of:
1) Removing abnormal data caused by abnormal operation of the monitoring equipment and the power quality monitoring system;
2) Judging the voltage sag event with the occurrence time interval not exceeding 60s as repeated data and only preserving one item;
3) Voltage dip events with durations exceeding 5000ms are rejected.
4. The method for evaluating the severity of a voltage sag in a power grid based on ITIC curves according to claim 1, wherein the type of voltage sag event at step S2 is determined as follows:
0≤T x ＜20(1)20≤T x ＜500(2)500≤T x ＜5000(3)
wherein T is x For the duration of the extraction of event x, x=1, 2,3 … …, n, n is the total number of dip events in ms, and according to the ITIC curve, if equation (1) is satisfied, the dip event is a first type of dip event, wherein the dip depth reference value V of the first type of dip event ref 0%; if the formula (2) is satisfied, the voltage sag event is a second-class voltage sag event, wherein the voltage sag depth of the second-class voltage sag event is a reference value V ref 70%; if the formula (3) is satisfied, the voltage sag event is a third type of voltage sag event, wherein the voltage sag depth of the third type of voltage sag event is a reference value V ref 80%.
5. The method for evaluating the severity of a sag of a power grid based on ITIC curves according to claim 1, wherein the statistical manner of step S3 is as follows:
wherein N is j M is the number of voltage sag events in the jth region of the non-damaged region of the ITIC curve equipment j P is the total number of voltage sag events in the area j Voltage sag events for a device no damage zone the duty cycle of all voltage sag events in that zone.
6. The method for evaluating the severity of a power grid voltage sag based on an ITIC curve according to claim 1, wherein the fraction obtained by the duty cycle is calculated as follows:
G 1 ＝(1-P j )×100
wherein G is 1 Fractional, P, fraction of the voltage sag event duty cycle for the non-damaged area of the regional equipment j Voltage sag events for a device no damage zone the duty cycle of all voltage sag events in that zone.
7. The method for evaluating the severity of the voltage sag of the power grid based on the ITIC curve according to claim 1, wherein the average voltage sag depth scoring table is obtained by an expert scoring method, and the average voltage sag depth scoring table divides the average voltage sag depth into different fractional segments according to the numerical value, and the higher the obtained fraction, the lower the average voltage sag depth in the region.
8. The method for evaluating the severity of a voltage dip of a power grid based on an ITIC curve according to claim 1, wherein the average voltage dip depth in the step S4 is the average voltage dip depth in the region by taking the ITIC curve as a reference, counting the voltage dip depths of each voltage dip event relative to the ITIC curve, and adding the counted voltage dip depths to average;
specifically, for a voltage dip event, the voltage dip depth V relative to the ITIC curve i The method comprises the following steps:
V i ＝V x -V ref
wherein V is x The voltage sag depth of the xth voltage sag event in the data preprocessed in the step S1 is V ref A voltage sag depth reference value which is the category to which the voltage sag event x belongs;
the average voltage sag depth of all voltage sag events in the non-damaged area of the ITIC curve equipment in the area is calculated by adopting the formula (4):
wherein L represents the average voltage sag depth of the region, N represents the total number of voltage sag events of the region, N represents the number of voltage sag events of the region, and V i Is the voltage dip depth of the ith voltage dip event relative to the ITIC curve.
9. The method for evaluating the severity of a voltage dip in a power grid based on ITIC curves according to claim 1, wherein the composite score of the severity of the voltage dip in a region of step S5 is calculated as follows:
G＝ω 1 ·G 1 +ω 2 ·G 2 (5)
wherein G is the comprehensive score of the severity of the voltage sag in the region, G 1 Fractional, G, of the duty cycle of the voltage sag event in the non-damaged area of the device 2 The fraction, ω, of the average voltage dip depth for that region 1 And omega 2 G in the comprehensive score of the severity of the voltage sag 1 And G 2 Is a weight of (a).
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| CN113656237A (en) * | 2021-07-16 | 2021-11-16 | 华南理工大学 | Load voltage sag immunity rating method, system, device and medium |
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| CN107561347B (en) * | 2017-08-16 | 2020-11-03 | 广东电网有限责任公司广州供电局 | Method and system for evaluating severity of voltage sag |
| CN108181527A (en) * | 2017-12-30 | 2018-06-19 | 国网天津市电力公司电力科学研究院 | A kind of appraisal procedure of the voltage dip synthesis severity based on energy indexes |
| CN108629525B (en) * | 2018-05-15 | 2022-09-27 | 国网上海市电力公司 | Node voltage sag severity evaluation method considering load importance degree |
| CN108921409B (en) * | 2018-06-21 | 2021-10-15 | 国网江苏省电力有限公司电力科学研究院 | Voltage sag severity grade determination method |
| CN109190164A (en) * | 2018-07-30 | 2019-01-11 | 贵州万峰电力股份有限公司 | Severity multi objective appraisal procedure temporarily drops in node voltage |
| CN109301835B (en) * | 2018-11-21 | 2020-08-04 | 广东电网有限责任公司 | Distribution network voltage sag severity evaluation method considering user utility |
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