3.1

Data acquisition and processing

The switch SOE signal analysis is connected to the total station accident and interval accident total signals through the measurement center, combined with the power outage plan of the business center, to eliminate planned power outages and other power outage events, and use real-time load data to determine the effectiveness of the final synthetic fault. First, preprocess the total accident signal of the switch, retrieve the switch name and fault description information, and filter out the information containing capacitor, reactor, energy storage battery, battery pack, bus coupler, test, local control, segmentation, bus denominator, Recording of 21 types of information such as reactive power, isolating switches, voltage transformers, arc suppression coils, etc., because this type of data is large in volume and cannot be used as a basis for switch tripping. At the same time, some dirty data is filtered out, such as signals without switch IDs and event identifiers. After that, the signal is filtered twice, and the fault content includes “protection action reset”, “zero sequence I section action reset”, “zero sequence II section action reset”, “reclosing action reset”, “reclosing reset”, ” Recloser outlet reset” and other related information are considered to be secondary equipment resets and are filtered out without processing.

3.2

Data analysis

The total accident signals are grouped into substations, and the switch signals in the same station are analyzed uniformly. The inspection signal is judged after the substations are grouped. If there is an inspection signal in a certain substation group, the substation is considered to be in an inspection state. Since the signals are relatively dense, the signals under the same station are segmented and processed at intervals of 30 seconds. It is divided into three situations: pure total signal processing for interval accidents[8], pure total signal processing for all-station accidents[9], and total mixed signal processing for all-station and interval accidents.

For interval accidents, if the interval between two accidents does not exceed 30 minutes, they can be merged. Using the switch as the key object for retrieval, the end time of the previous fault and the start time of the new fault, which do not exceed 30 minutes, can be merged.

4.1

Dedicated line power outage research and judgment

For dedicated line power outages, the tripping of the incoming and outgoing line switches of the dedicated line is monitored. According to the D5000 system switch trip signal and protection action signal, the dedicated line equipment resources are obtained through the matching dedicated line incoming and outgoing switch ID, and the dedicated line power outage event is determined. Based on the relationship between the marketing line and the user, combined with the multi-power status of the special change user, the power outage of the users affected by the special line is determined. The process is shown in Figure 3:

Figure. 3

Dedicated line power outage research and judgment process and conclusion

4.2

Research and judgment on power outage of entire feeder line

In view of the power outage of the entire feeder line, the direct acquisition of the line outlet switch trip signal and the summarization and merging of distribution transformer power outage events are realized. The two research and judgment results serve as the basis for mutual verification, and the merger of the research and judgment results can be achieved. The process is shown in Figure 4:

Figure. 4

Research and judgment process and conclusion on complete power loss of feeder line

4.3

Research and judgment on power outage of feeder area

For power outages in feeder area, it can be achieved through direct acquisition of branch line/section line trip information and summary and merger of distribution transformer power outage events. The two research and judgment results serve as the basis for mutual verification, and the merger of the research and judgment results can be achieved. The process is shown in Figure 5:

Figure. 5

Research and judgment process and conclusion on power outage of feeder area

4.4

Research and Judgment on Distribution Transformer Loss of Power

For distribution transformer power outage, the distribution power outage event can be analyzed and judged by using the station area main meter power outage signal reported by the collecting device or the special transformer terminal, and the distribution transformer main open position change signal reported by the distribution transformer. The two research and judgment results can be used as a basis for mutual verification, and the merger of the research and judgment results can be achieved. The process is shown in Figure 6:

Figure. 6

Distribution transformer power loss research and judgment process and conclusion

4,5

Research and Judgment on Low Voltage Line Outage

For low-voltage line power outages, the low-voltage line switch opening signal and HPLC low-voltage household meter power outage events can be summarized and combined for research and judgment. The two research and judgment results can be used as a basis for mutual verification, and the merger of the research and judgment results can be achieved. The process is shown in Figure 7:

Figure. 7

Low-voltage line power outage research and judgment process and conclusion

5.1

Data model transformation

The enterprise-level real-time measurement center uses stream processing to consume message queue data in real time, and combines the archive data and topology data in the cache to perform model conversion.

The collected subject data (switch protection action, switch status, switch current and voltage, switch trip signal) are associated with the transformer and switch relationship data through the switch ID to obtain the resource ID. Then, it is associated with the distribution and transformation account data through the resource ID together with the power outage signal data in the station area, and the resource name, affiliated feeder, power supply unit, affiliated city, affiliated district and county, and maintenance team are obtained. Action time, power outage event source, and action type are obtained from real-time collected data. The source of the power outage event is the topic in the message queue. The above results form medium voltage measurement data information.

The low-voltage side signal data is associated with the low-voltage user access point data through the resource ID to obtain the resource name, meter box, station area, power supply unit, affiliated city, affiliated district and county, and maintenance team. Action time, power outage event source, and action type are obtained from real-time collected data. The source of the power outage event is the topic in the message queue. The above results form low-voltage measurement data information.

Store the medium-voltage measurement data and low-voltage measurement data generated after model conversion into the collection library.

In the early morning of the next day, all the measurement data of the previous day will be pushed to the data center and entered into the history database.

5.2

Outage event compression

For power outage events from different event sources for the same device, the power outage events within 30 minutes between the power restoration time of the last power outage event and the power outage time of this power outage event can be merged into one power outage event. Single point power outage event compression algorithm is shown in Figure 8:

Figure. 8

Single point power outage event compression algorithm

Where D represents the power outage event source, n represents the sequence number of the power outage event source, sorted by the event source start time, Tstart and Tend represent the power outage and restoration time of each event source, and ΔT represents the difference between the power outage time of the latter event and the restoration time of the previous event. After executing the power outage event compression algorithm, n independent power outage events are compressed into one valid power outage event, which not only reduces the complexity of power outage event analysis, but also lays a solid foundation for the accuracy of power outage event judgment.

5.3

Judgment of effectiveness of power outage events

Mark each power outage event to see if it is a valid power outage event. If the power outage time is not empty, it will be considered valid if the power outage is longer than 10 minutes, otherwise it will be invalid; If there is power on but no power outage event, and there is no power outage signal within 24 hours, it is judged as invalid; There is a power outage time but no power on time and it is judged as valid. If the number of power outages exceeds 6 times within 24 hours, it will be deemed invalid for that day. The process is shown in Figure 9:

Figure. 9

Judgment of effectiveness of power outage events

5.4

Merge power outage events in the same area

Group the power outage events according to the area they belong to, and determine whether the superior level of the power outage equipment has a power outage. All sources of power outages are split into transformers or user outages. After completion and repair according to transformers or user outages, they are merged according to the line and switch to which the transformer belongs, and the corresponding meter box and station area of the user. At the same time, they are merged according to the time range of the outage. Form a unified collection of power outage events for use by other businesses. The merging rules are as follows.

Non-user power outage event synthesis is used to determine the switch and line to which the transformer belongs based on the transformer outage. If the power outage time of the transformer under the switch of the same line is within 45 minutes, and there are more than two power outage transformers (at least one public transformer), it will be determined as a line side power outage. The power outages are collected according to the line, and the earliest transformer power outage time and the latest power outage time are taken as the start and end time of the power outage event.

The user power outage event synthesis is based on the user’s power outage and searches the meter box and station area it belongs to. If the user power outage time is within 15 minutes under the same meter box in the same station area, and there are more than two users, it is determined to be a single meter box power outage. If the power outages for different meter boxes are collected according to the station area, the earliest power outage time and the latest power outage time are taken as the start and end time of the power outage event.

5.5

Distribution network fault due to sudden drop in feeder load

After a fault occurs in the distribution network, because the fault current is greater than the line switch protection setting, the upstream line switch closest to the fault point will trip. All distribution transformers and their loads downstream of the switch are cut off, resulting in a sudden drop in power at the feeder outlet. When line losses are ignored, the feeder load sag is equal to the load proportion of the trip switch. Therefore, if the load proportion of each switch before the fault can be calculated, the authenticity of the fault trip switch can be determined by comparing the feeder load sag and the load proportion of each switch after the fault. So, after a fault occurs, the historical load data of each distribution transformer can be extracted immediately from the purchasing system, and the active load of each distribution transformer can be predicted at the time of the fault using load forecasting. Then combined with the topological relationship of “substation-line-switch-distribution transformer”, the distribution transformer load prediction values downstream of each switch on the line are accumulated to obtain the load proportion of each switch at the time of the fault. Finally, fault analysis and judgment are carried out based on the load sag[10] and the load proportion of each switch.