Disclosure of Invention
The invention aims to solve the problems that the existing energy storage power station key equipment fault diagnosis method is low in response speed and cannot analyze the equipment root fault reasons reflected by abnormal states, and the power station field refined operation and maintenance requirements are difficult to meet, and provides an energy storage power station key equipment fault diagnosis early warning method based on data mining.
In order to solve the technical problems, the technical scheme includes that the fault diagnosis early warning method for the energy storage power station key equipment based on data mining comprises the following steps of S01, establishing a diagnosis early warning rule base according to historical data, establishing a response operation and maintenance suggestion base aiming at various rules, S02, collecting and processing abnormal signals in a period of time, performing fuzzy matching with the rule base, sending out fault diagnosis early warning information if matching is successful, otherwise, only giving out warning on the abnormal state, and S03, if the system sends out diagnosis early warning information, giving out corresponding operation and maintenance suggestions according to different fault types deduced in the step S02.
Further, the step S01 of establishing a diagnosis fault rule base and an operation and maintenance suggestion base comprises the steps of initially screening influence parameters which possibly cause equipment faults from operation and maintenance parameters of an original energy storage power station according to engineering experience, then selecting corresponding influence parameter data in a complete period from a historical database and preprocessing, S12 of analyzing the correlation between the initially screened influence parameters and the faults according to the historical data to determine parameters with the correlation meeting requirements as main influence factors, S13 of discretizing the historical data of the main influence factors according to set thresholds, and establishing an equipment fault diagnosis early warning rule base by adopting a data mining algorithm, S14 of formulating operation and maintenance suggestions according to fault types corresponding to different rules in the rule base and establishing the operation and maintenance suggestion base.
Further, the correlation between a certain parameter and a fault is analyzed by adopting a K-neighbor mutual information algorithm, and the specific method is that a correlation threshold value theta is firstly set, then mutual information MI between a certain parameter and the fault is calculated by utilizing the K-neighbor mutual information algorithm, the correlation threshold value theta and the mutual information MI are compared, if MI is smaller than theta, the parameter is abandoned, and otherwise the parameter is recorded.
Further, a group of influence parameters related to faults are determined by adopting an Apriori association rule algorithm, so that a device fault diagnosis early warning rule base is established; b, scanning history data of the discretized main influence factors, finding out all items meeting the minimum support degree, namely a frequent 1 item set, c, based on the frequent 1 item set, scanning history data of the discretized main influence factors, finding out a frequent 2 item set, cycling the process until no new frequent k+1 item set exists, wherein k is the category number of the main influence factors, d, calculating whether confidence between the item sets meets the condition that the confidence is not less than the minimum confidence, and determining strong association.
Further, in the process of generating frequent k+1 item sets by frequent k item sets, a connection step and a pruning step are adopted to improve efficiency, the connection step is used for finding out frequent k+1 item set L k+1, the frequent k item sets in L k are connected to generate candidate sets C k+1, in order to ensure that the generated item sets are irrelevant, if and only if the previous k-1 items after 2 frequent k item sets are ordered are identical, the pruning step is used for finding out item sets with C k+1 meeting the minimum support, the support of each item set is calculated by directly scanning historical data of main influence factors after discretization, and when C k+1 is larger than a set threshold value, C k+1 is compressed by adopting priori knowledge.
Further, the step S02 includes the steps of collecting real-time data of parameters screened in the step S01, recording signal data if abnormal signals appear, the step S22 includes the steps of counting abnormal signals appearing in a period of time after the first data are collected in the step S21, recording the data of the abnormal signals, the step S23 includes the steps of carrying out discretization processing on the data recorded in the step S21 and the step S22 according to a set threshold value, carrying out fuzzy matching on the processed real-time data of the parameters and a diagnosis and early warning rule base, and the step S24 includes the steps of sending diagnosis and early warning information aiming at different fault types and levels if the matching is successful, otherwise, carrying out warning on the abnormal state only through vibration.
Further, the step S03 comprises 2 steps, specifically, if the step S02 is successfully matched, the diagnosis early warning information is sent out, meanwhile, corresponding operation and maintenance suggestions are accurately matched in an operation and maintenance library according to different fault types, and the matched operation and maintenance suggestions in the step S31 are pushed through a picture in the step S32.
The method has the beneficial effects that the K-neighbor mutual information and the Apriori association rule algorithm are adopted to realize fault diagnosis early warning of the key equipment of the energy storage power station, and compared with the traditional warning strategy, the method can deeply mine the hidden association between each operation parameter of the key equipment of the energy storage power station and the fault information, effectively shortens the fault diagnosis time, provides simple and efficient maintenance suggestions, and provides fine guidance for operation and maintenance personnel. Compared with other intelligent algorithm diagnosis early warning strategies, the method aims at the problems of various key equipment parameters of the energy storage power station, strong coupling, huge volume of historical data and the like, combines engineering experience, adopts a K-nearest neighbor mutual information algorithm to screen main influencing factors of faults, can reduce manual screening workload and errors, and improves execution efficiency. Meanwhile, the expert database built by the method supports functions of rule expansion, modification, deletion and the like, and can provide support for new operation and maintenance requirements of the energy storage power station in the later period.
The method has the advantages that through monitoring the operation state of key equipment of the energy storage power station in real time, when faults are about to occur or occur, a plurality of collected early warning or alarming signals are subjected to fuzzy matching with a rule base within a certain time range, potential hazards possibly existing in the operation process of the system are analyzed, the abnormality or the fault type of the energy storage system is timely and accurately judged, abnormal working condition limitation, fault protection and audible and visual alarm are automatically implemented, and corresponding operation and maintenance suggestions are given.
Detailed Description
The invention will be further described with reference to the drawings and the specific examples.
Example 1
When the power grid fails, the EMS can receive action event sequence records of power grid switches and relay protection devices sent by different RTUs, substation automation systems and other systems, and the events are arranged in time sequence and then stored in a historical database as historical information. According to different key equipment of the energy storage power station, the method can be mainly divided into PCS diagnosis early warning and battery system diagnosis early warning.
(1) PCS diagnosis early warning
Diagnosis and early warning are carried out according to the PCS running state and real-time data, and operations such as shutdown maintenance, connector fastening, fault module replacement, overhaul and the like are carried out on the PCS. The main fault types include the following:
a) Ac voltage is too high and too low
B) The alternating frequency is too high and too low
C) The DC voltage is too high and too low
D) Overload, overheat and short-circuit of converter
E) Overheat of radiator
F) Island of converter
G) DSP failure
(2) Battery system diagnosis and early warning
When the battery system operates, if the voltage, current, temperature and other analog quantities of the battery exceed the safety protection limit value, the on-site fault isolation can be implemented, the battery pack with the problem is taken out of operation, and meanwhile, protection information is reported. The main fault types are as follows:
a) Overvoltage of battery
B) Under-voltage of battery
C) Over-temperature of battery
D) Low temperature battery
E) Battery overcurrent
F) SOC out-of-limit
As shown in fig. 1, a fault diagnosis and early warning method for key equipment of an energy storage power station based on data mining mainly comprises the following specific implementation steps:
1. And establishing and maintaining two libraries, namely establishing a diagnosis early warning rule library according to historical data, and establishing a corresponding operation and maintenance suggestion library aiming at various rules. The rule base and the operation and maintenance base can be maintained in the background of supplementation, deletion, modification and the like according to the requirements of different application scenes;
2. processing an abnormal signal in a period of time, performing fuzzy matching with a rule base, and sending out fault diagnosis early warning information if the matching is successful, otherwise, only alarming for the abnormal state;
3. and (4) pushing operation and maintenance suggestions, namely if the system sends diagnosis early warning information, giving out corresponding operation and maintenance suggestions according to the fault type pushed out in the step (2), as shown in fig. 4.
According to the specific embodiment of the present invention, the above-mentioned step 1 "two-library" establishment and maintenance process includes four steps, specifically as follows:
(1) And preliminarily screening influence parameters which cause the faults of the energy storage power station equipment from a large number of operation and maintenance parameters according to engineering experience. Selecting data in a complete period from a historical database and preprocessing, wherein the preprocessing comprises the processing of abnormal values and vacant values;
(2) Analyzing the correlation between the preliminarily screened parameters and the faults according to the historical data, and determining the parameters with the correlation meeting the requirements as main influencing factors;
(3) Discretizing the historical data of the parameters according to a set threshold value, and establishing a rule base by adopting a data mining algorithm. The rule base can be expanded subsequently as required;
(4) And formulating operation and maintenance suggestions according to fault types corresponding to different rules in the rule base, and establishing an operation and maintenance suggestion base. The operation and maintenance library can be expanded subsequently as required.
The correlation analysis method in the step 2 is a K-neighbor mutual information algorithm, and the data mining algorithm for establishing the rule base is an Apriori association rule algorithm.
Mutual information (Mutual information, MI) is a method for measuring the degree of interdependence of two random variables, and is based on the concept of entropy in information theory. The larger the mutual information of the two random variables, the stronger the correlation. The main influence factors of the faults are selected according to mutual information, the influence of multivariable coupling on equipment faults is not considered, and the defects of high-dimensional operation amount, low precision and the like exist. The K-neighbor mutual information method can avoid directly calculating probability density and has good evaluation effect on complex nonlinear relations.
The definition of the mutual information shows that the smaller the mutual information MI (X, Y) is, the smaller the shared information amount of the sequence X and the sequence Y is, and the smaller the sequence correlation is, whereas the larger the mutual information MI (X, Y) is, the more the shared information amount of the sequence X and the sequence Y is, and the larger the sequence correlation is. Therefore, the main influencing factors of the key equipment faults of the energy storage power station can be determined according to the MI.
As shown in FIG. 2, the process of screening the main influencing factors of the faults by using the K-neighbor mutual information method comprises the steps of firstly setting a correlation threshold value theta, then calculating mutual information MI between a certain fault and the fault by using a K-neighbor mutual information algorithm, comparing the correlation threshold value theta with the mutual information MI, and discarding the parameter if MI is smaller than theta, otherwise recording the parameter. If a plurality of main influencing factors are calculated, repeating the process, and calculating the correlation between other factors and faults.
Further explanation of steps (1) and (2) is made in accordance with the description of the K-nearest neighbor mutual information algorithm above:
The key equipment of the energy storage power station comprises a battery body, a BMS, a PCS and the like, the equipment parameters are various, the coupling is strong, the volume of historical data is huge, and the main influencing factors causing faults are difficult to determine. Therefore, the invention combines engineering experience to preliminarily screen out influence parameters which cause equipment faults from a plurality of operation and maintenance parameters such as current, voltage, frequency, temperature, pressure and the like. And selecting data in a complete period from the historical database for preprocessing, including processing of abnormal values and vacant values. A correlation threshold is then set, i.e. above which the parameter is considered to be sufficiently strongly correlated with the fault to be the main cause of the fault occurrence. And finally, analyzing the correlation between the preliminarily screened parameters and the equipment faults by adopting a K-nearest neighbor mutual information algorithm according to historical data, and determining 3-5 parameters exceeding a correlation threshold as final parameters for establishing a rule base.
The association rules may find internal association mechanisms between 2 or more variables and predict event occurrence by analyzing the established association mechanisms. When key equipment such as PCS (personal communication System) and the like breaks down, fault related information is recorded in an EMS system log and stored in a historical database, and correlation rules can be applied to extract dependence and correlation between fault types and fault phenomena by analyzing historical data so as to obtain mode characteristics of various faults and guide diagnosis and early warning processes.
The correlation analysis results are typically measured using two key indicators of support and confidence. Taking the item set X and the item set Y as examples, the support S refers to the probability that the item sets X and Y occur simultaneously, and the confidence C refers to the probability that the item set Y occurs when the item set X occurs. Where an item set is a collection of items, an item set containing k items is referred to as a k item set, e.g., the collection { A, B, C } is a 3 item set.
In general, a term set satisfying the support degree not less than the minimum support degree is referred to as a frequent term set, while a rule satisfying the support degree not less than the minimum support degree and the confidence degree not less than the minimum confidence degree is referred to as a strong rule, in which the minimum support degree s_min and the minimum confidence degree c_min are used to define thresholds of the support degree and the confidence degree.
The mining of the association rule in this embodiment is to obtain mode features of various faults, that is, a group of signals corresponding to the faults, as shown in fig. 3, that is, a specific flow is as follows:
a. Setting a minimum support degree and a minimum confidence degree, b, scanning historical data of the discretized main influence factors, finding out all items meeting the minimum support degree, namely a frequent 1 item set, c, based on the frequent 1 item set, scanning the historical data of the discretized main influence factors, finding out a frequent 2 item set, cycling the process until no new frequent k+1 item set exists, k is the category number of the main influence factors, d, calculating whether the confidence degree among the item sets meets the condition that the confidence degree is not less than the minimum confidence degree, and determining strong association.
The method is characterized in that the whole database is required to be completely scanned every time a new item set is searched, the execution efficiency is low, a connection step and a pruning step are adopted in the process of generating frequent k+1 item sets by frequent k item sets, the connection step is used for finding out frequent k+1 item set L k+1, connecting frequent k item sets in L k to generate candidate set C k+1, in order to ensure that the generated item sets are irrelevant, if and only if the first k-1 items after 2 frequent k item sets are ordered are identical, the pruning step is used for finding out item sets with the minimum support degree of C k+1, the support degree of each item set is calculated by directly scanning historical data of main influence factors after discretization, and when C k+1 is larger than a set threshold value, the prior knowledge is adopted for compressing C k+1.
Because the association rule algorithm can only process Boolean data, and the values of parameters such as current, voltage, temperature and the like of key equipment of the energy storage power station are continuous, the historical data of the parameters screened in the step (2) are required to be discretized according to a set threshold value. Taking the current as an example, i.e. when the current exceeds a set threshold, it is noted "1", otherwise it is noted "0". And then, establishing a diagnosis early warning rule base by combining a confidence coefficient formula through a connection step and a pruning step by using discretized data and adopting an Apriori association rule algorithm.
According to the specific embodiment of the invention, the equipment fault diagnosis and early warning process in the step 2 comprises 4 steps, and the specific steps are as follows:
(1) Acquiring real-time data of the parameters screened in the step 1, and recording the signal data if abnormal signals occur;
(2) Counting abnormal signals occurring in a period of time from the time when the first data is acquired in the step (1) and recording the data of the abnormal signals;
(3) Discretizing the data recorded in the steps (1) and (2) according to a set threshold value, and carrying out fuzzy matching on the processed parameter real-time data and a diagnosis early warning rule base;
(4) If the matching is successful, different diagnosis early warning information such as sound, light, vibration, pushing pictures and the like shown in fig. 5 is sent out aiming at different fault types and levels, otherwise, the abnormal state is only warned through vibration.
According to a specific embodiment of the present invention, the operation and maintenance suggestion pushing process in the step 3 includes 2 steps, which are specifically as follows:
(1) If the step 2 is successful in matching, sending diagnosis early warning information, and simultaneously, accurately matching corresponding operation and maintenance suggestions in an operation and maintenance library according to different fault types;
(2) Pushing the matched operation and maintenance suggestions in the step (1) through a picture.
According to the specific embodiment of the invention, taking the battery module fault as an example, the whole flow of the method is further explained:
And analyzing collected historical operation data of signals such as battery current and voltage, battery compartment temperature and pressure, fire protection out-of-limit of a battery system and the like through a K neighbor mutual information algorithm by combining engineering experience to obtain parameters such as battery cell voltage, battery compartment temperature, fire protection of the battery system and the like and larger faults MI of the battery module. Discretizing the parameters according to a set threshold value, wherein the result after the discretization treatment is that the overvoltage of the battery monomer is recorded as 1, the overtemperature of a battery compartment is recorded as 1, the fire-fighting out-of-limit alarm of a battery system is recorded as 1, and the fault of a battery module is recorded as 1. And determining { battery cell overvoltage, battery temperature overhigh, battery system fire alarm } > battery module fault strong association rule according to the Apriori association rule algorithm.
When the energy storage power station operates, when one of the parameters { battery cell overvoltage, battery temperature is too high and battery system fire alarm } acquired in real time appears, the system starts timing and automatically carries out fuzzy matching with the rule base. If two other abnormal signals occur within 30 seconds, triggering a rule base under the action of the combined alarm signal, adopting the modes of sound, light, vibration, pushing pictures and the like for early warning, pushing information such as maintenance suggestions and the like, and providing references for operation and maintenance overhaulers.
The foregoing has outlined the principles and embodiments of the present invention in order that the detailed description of the invention may be better understood, and in order that the present invention may be better understood. Various other modifications and variations which do not depart from the gist of the invention may be made by those skilled in the art in light of the present disclosure and are intended to be within the scope of the invention.