State evaluation method and system for low-voltage reactive power compensation equipment, storage medium and equipment

Abstract

The embodiment of the invention discloses a low-voltage reactive power compensation equipment state evaluation method, and the method comprises the steps: collecting basic data of low-voltage reactive power compensation equipment, the basic data comprises a voltage, a power factor, an active load, a distribution transformer low-voltage side reactive load, a distribution transformer low-voltage side active power, a reactive power, a common compensation capacitor rated capacity, a separate compensation capacitor rated capacity and a voltage abnormal duration; determining an evaluation index according to the basic data; and determining the operation state of the low-voltage reactive power compensation equipment according to the evaluation index. According to the method, the basic data is collected, the evaluation index is determined according to the basic data, the operation state of the low-voltage reactive power compensation equipment is further judged, the health condition and performance of the equipment can be comprehensively and objectively evaluated, the accuracy of state evaluation of the low-voltage reactive power compensation equipment can be improved, and the working efficiency is improved. And real-time monitoring and early warning of the operation state of the equipment can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of distribution network operation control, and particularly to a method, system, storage medium and device for evaluating the state of low-voltage reactive power compensation equipment. Background Art

[0002] Reactive power compensation equipment plays a crucial role in the distribution network. Its function is to provide or absorb reactive power to maintain voltage stability, reduce line losses, and improve the power factor of the power system. The application of reactive power compensation equipment can effectively solve the problem of insufficient or excessive reactive power in the distribution network, thus ensuring the safe and stable operation of the power system. However, the compensation effect of reactive power compensation equipment is affected by various factors, including equipment configuration, load changes, system operation modes, etc., which makes the evaluation and management of reactive power compensation equipment complex.

[0003] The existing evaluation methods for low-voltage reactive power compensation equipment of distribution transformers mainly rely on manual inspection and empirical judgment. Evaluators evaluate the operation status of the equipment by observing the operation status of the equipment and consulting operation records. The evaluation results of this method depend on the experience and skills of the evaluators, are easily affected by human factors, and lack data support. Summary of the Invention

[0004] Based on this, in view of the above problems, it is necessary to propose a method for evaluating the state of low-voltage reactive power compensation equipment.

[0005] A method for evaluating the state of low-voltage reactive power compensation equipment, the method comprising the following steps:

[0006] Collect basic data of the low-voltage reactive power compensation equipment, the basic data including voltage, power factor, active load, reactive load, active power on the low-voltage side of the distribution transformer, reactive power on the low-voltage side of the distribution transformer, rated capacity of the common compensation capacitor, rated capacity of the split compensation capacitor, and abnormal voltage duration;

[0007] Determine evaluation indicators according to the basic data;

[0008] Determine the operation state of the low-voltage reactive power compensation equipment according to the evaluation indicators.

[0009] In the above solution, the evaluation indicators include: power factor, compensation state, matching rate, voltage qualification rate, asymmetry degree, and health degree of the low-voltage reactive power compensation equipment;

[0010] Determine the power factor according to the active power on the low-voltage side of the distribution transformer and the reactive power on the low-voltage side of the distribution transformer;

[0011] Determine the compensation state according to the power factor, severity threshold, and rated capacity of the distribution transformer;

[0012] Determine the matching rate according to the rated capacity of the common compensation capacitor and the rated capacity of the separate compensation capacitor;

[0013] Determine the voltage qualification rate according to the abnormal voltage duration;

[0014] Determine the asymmetry degree according to the active load and the reactive load;

[0015] Determine the health degree of the low-voltage reactive power compensation equipment according to the power factor.

[0016] In the above solution, the determination of the power factor according to the active power on the low-voltage side of the distribution transformer and the reactive power on the low-voltage side of the distribution transformer specifically includes:

[0017] Determine the power factor according to the following formula:

[0018]

[0019] where, cosA 1 , cosB 1 and cosC 1 are the power factors of phase A, phase B, and phase C on the low-voltage side of the distribution transformer of the low-voltage reactive power compensation equipment respectively, P a , P b , P c are the active powers of phase A, phase B, and phase C on the low-voltage side of the distribution transformer of the low-voltage reactive power compensation equipment respectively, Q a , Q b , Q c are the reactive powers of phase A, phase B, and phase C on the low-voltage side of the distribution transformer of the low-voltage reactive power compensation equipment respectively.

[0020] In the above solution, the determination of the compensation state according to the power factor, the severity threshold, and the rated capacity of the distribution transformer specifically includes:

[0021] When the power factor is between 0 and 0.92 and the reactive power is greater than the severity threshold, it is determined that the low-voltage reactive power compensation equipment is in a serious under-compensation state:

[0022] 0 < cosφ < 0.92 and Q > demp·S n

[0023] When the power factor is less than 0 and the reactive power is less than the severity threshold, it is determined that the low-voltage reactive power compensation equipment is in an over-compensation state:

[0024] cosφ < 0 and Q < demp·S n

[0025] where, S nHere, \(S_{rated}\) is the rated capacity of the affiliated distribution transformer, \(demp\) is the severity threshold, \(Q\) is the reactive power load, and \(\cos\varphi\) is the power factor of a certain phase of the low-voltage reactive power compensation equipment.

[0026] In the above solution, determining the matching rate according to the rated capacity of the shunt capacitor and the rated capacity of the series capacitor specifically includes:

[0027] Determine the matching rate according to the following formula:

[0028]

[0029] where \(Q\) gh1 , \(Q\) gh2 , \(\cdots\), \(Q\) gn5 are the rated capacities of shunt capacitor 1, shunt capacitor 2, shunt capacitor 3, shunt capacitor 4, and shunt capacitor 5 respectively, \(Q\) gh1 , \(Q\) gh2 are the rated capacities of series capacitor 1 and series capacitor 2 respectively, \(S\) n is the capacity of the affiliated low-voltage reactive power compensation equipment, and \(C\) s is the matching rate.

[0030] In the above solution, determining the voltage qualification rate according to the abnormal voltage duration specifically includes:

[0031] Determine the voltage deviation rate according to the abnormal voltage duration;

[0032] The voltage deviation rate includes the low voltage rate and the high voltage rate, and their calculation formulas are as follows:

[0033]

[0034] where \(V\) lT is the duration of the low voltage at the low-voltage side of the distribution transformer of the low-voltage reactive power compensation equipment within one day, \(V\) hT is the duration of the high voltage at the low-voltage side of the distribution transformer of the low-voltage reactive power compensation equipment within one day, \(N\) is the total number of moments, \(V\) 1 is the low voltage rate, and \(V\) h is the high voltage rate.

[0035] Determine the voltage qualification rate according to the voltage deviation rate:

[0036] \(V\) q = 1 - \(V\) l - \(V\) h

[0037] where \(V\) q is the voltage qualification rate, \(V\) l is the low voltage rate, and \(V\) h is the high voltage rate.

[0038] In the above solution, determining the asymmetry degree according to the active load and the reactive load specifically includes:

[0039] Determine the maximum active load asymmetry degree P according to the following formula ubmax :

[0040]

[0041] Determine the average active load asymmetry degree P according to the following formula ubav :

[0042]

[0043] Determine the maximum reactive load asymmetry degree Q according to the following formula ubmax :

[0044]

[0045] Determine the average reactive load asymmetry degree Q according to the following formula ubav :

[0046]

[0047] Wherein, P ubmax is the maximum active load asymmetry degree, P ubav is the average active load asymmetry degree, Q ubmax is the maximum reactive load asymmetry degree, Q ubav is the average reactive load asymmetry degree, P ak , P bk , P ck are the active loads of the a-phase, b-phase and c-phase of the low-voltage side of the distribution transformer of the low-voltage reactive power compensation device respectively, Q ak , Q bk , Q ck are the reactive loads of the a-phase, b-phase and c-phase of the low-voltage side of the distribution transformer of the low-voltage reactive power compensation device respectively, S n is the capacity of the affiliated distribution transformer, and N is the total number of moments;

[0048] Determine the asymmetry degree according to the maximum active load asymmetry degree P ubmax , the average active load asymmetry degree P ubav , the maximum reactive load asymmetry degree Q ubmax and the average reactive load asymmetry degree Q ubav .

[0049] In the above solution, determining the health degree of the low-voltage reactive power compensation device according to the power factor specifically includes:

[0050] Calculate the mean cos mean and the standard deviation cos std of the power factor;

[0051] Obtain the mutual information i;

[0052] Determine the health of the low-voltage reactive power compensation device according to the mean value cos mean, the standard deviation cos std and the mutual information i:

[0053]

[0054] Wherein, cos mean is the mean value of the power factor, cos std is the standard deviation of the power factor, i is the mutual information, and h is the health of the low-voltage reactive power compensation device.

[0055] In the above solution, the determining the operating state of the low-voltage reactive power compensation device according to the evaluation index specifically includes:

[0056] Establish a comprehensive evaluation model for the state of the low-voltage reactive power compensation device;

[0057] Input the evaluation index into the comprehensive evaluation model for the state of the low-voltage reactive power compensation device to obtain an output result;

[0058] Evaluate the operating state of the low-voltage reactive power compensation device according to the output result.

[0059] This application also proposes a system for evaluating the state of a low-voltage reactive power compensation device, and the system includes: a data acquisition unit, a judgment index determination unit, and a low-voltage reactive power compensation device state evaluation unit;

[0060] The data acquisition unit is used to collect the basic data of the low-voltage reactive power compensation device, and the basic data includes voltage, power factor, active load, reactive load, active power on the low-voltage side of the distribution transformer, reactive power on the low-voltage side of the distribution transformer, rated capacity of the common compensation capacitor, rated capacity of the split compensation capacitor, and abnormal voltage duration;

[0061] The judgment index determination unit is used to determine the evaluation index according to the basic data;

[0062] The low-voltage reactive power compensation device state evaluation unit is used to determine the operating state of the low-voltage reactive power compensation device according to the evaluation index.

[0063] This application also proposes a readable storage medium, storing a computer program, and when the computer program is executed by a processor, the processor is caused to execute the following steps:

[0064] Collect the basic data of the low-voltage reactive power compensation device, and the basic data includes voltage, power factor, active load, reactive load, active power on the low-voltage side of the distribution transformer, reactive power on the low-voltage side of the distribution transformer, rated capacity of the common compensation capacitor, rated capacity of the split compensation capacitor, and abnormal voltage duration;

[0065] Determine evaluation indicators based on the basic data;

[0066] Determine the operating status of the low-voltage reactive power compensation device according to the evaluation indicators.

[0067] This application also proposes a computer device, including a memory and a processor. The memory stores a computer program, and the computer program is executed by the processor to perform the following steps:

[0068] Collect the basic data of the low-voltage reactive power compensation device, where the basic data includes voltage, power factor, active load, reactive load, active power on the low-voltage side of the distribution transformer, reactive power on the low-voltage side of the distribution transformer, rated capacity of the common compensation capacitor, rated capacity of the split compensation capacitor, and abnormal voltage duration;

[0069] Determine evaluation indicators based on the basic data;

[0070] Determine the operating status of the low-voltage reactive power compensation device according to the evaluation indicators.

[0071] Adopting the embodiment of the present invention has the following beneficial effects: First, collect the basic data of the low-voltage reactive power compensation device, where the basic data includes voltage, power factor, active load, reactive load on the low-voltage side of the distribution transformer, active power on the low-voltage side of the distribution transformer, reactive power, rated capacity of the common compensation capacitor, rated capacity of the split compensation capacitor, and abnormal voltage duration; Determine evaluation indicators based on the basic data; Determine the operating status of the low-voltage reactive power compensation device according to the evaluation indicators. The present invention can comprehensively and objectively evaluate the health status and performance of the device by collecting basic data, determining evaluation indicators based on this basic data, and then judging the operating status of the low-voltage reactive power compensation device, improving the accuracy of the low-voltage reactive power compensation device status evaluation, facilitating real-time monitoring and early warning of the device operating status, and precise evaluation and optimized management of the reactive power compensation device status. Description of the Drawings

[0072] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0073] Among them,

[0074] Figure 1 It is a schematic flowchart of the low-voltage reactive power compensation device status evaluation method in an embodiment;

[0075] Figure 2 Shows the internal structure diagram of a computer device in an embodiment. Detailed implementation manners

[0076] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0077] In the following description, numerous specific details are given to provide a more thorough understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without one or more of these details. In other instances, in order to avoid confusion with the present invention, some well-known technical features are not described. It should be understood that the present invention can be implemented in different forms and should not be construed as limited to the embodiments presented herein. On the contrary, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the present invention to those skilled in the art.

[0078] The purpose of the terms used herein is only to describe specific embodiments and is not a limitation of the present invention. When used herein, the singular forms "a", "an" and "the" are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms "comprising" and / or "including", when used in this specification, identify the presence of the stated features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups. When used herein, the term "and / or" includes any and all combinations of the related listed items.

[0079] In order to thoroughly understand the present invention, detailed structures will be presented in the following description to explain the technical solutions proposed by the present invention. The optional embodiments of the present invention are described in detail below. However, in addition to these detailed descriptions, the present invention may also have other implementation manners.

[0080] The prior art evaluates the operating conditions of equipment through manual inspections, which requires a large amount of manpower and material resources, cannot timely grasp the operating state of the equipment, and has low evaluation efficiency. To solve the deficiencies of the existing evaluation methods, this application proposes a method for evaluating the state of low-voltage reactive power compensation equipment. By collecting the operating data of the equipment and performing calculations and analyses according to pre-set evaluation indicators, the operating state of the low-voltage reactive power compensation equipment is finally determined, and a decision-making basis is provided for the control strategy and capacity configuration of the low-voltage reactive power compensation equipment, thereby improving the effect of reactive power compensation and the operating efficiency of the power system.

[0081] For ease of understanding, the relevant terms involved in this application are introduced below.

[0082] (1) Power factor is an important parameter in the power system, representing the ratio of active power to apparent power. It reflects the efficiency of energy utilization in the circuit and is one of the important indicators for measuring the operating state of the power system.

[0083] (2) Shunt capacitor compensation refers to the capacitor bank installed centrally on the low-voltage bus of the distribution transformer in the low-voltage distribution network, which is used to compensate the reactive power of the entire distribution network. Shunt capacitor compensation can improve the power factor. By compensating the reactive power in the distribution network, it can improve the power factor of the distribution network, thereby reducing line losses and improving the utilization rate of electric energy.

[0084] (3) Split capacitor compensation refers to the capacitor banks installed separately on each branch of the low-voltage side of the distribution transformer or on the load side in the low-voltage distribution network, which is used to compensate the reactive power of local loads.

[0085] (4) Mutual information is a concept in information theory, which is used to quantify the mutual dependence relationship between two variables. It reflects the amount of information shared between two variables and can be used to evaluate the correlation, independence and the effectiveness of information transmission between variables.

[0086] As Figure 1 shown, in one embodiment, a method for evaluating the state of low-voltage reactive power compensation equipment is provided. The method for evaluating the state of low-voltage reactive power compensation equipment includes steps S101 to S103, which are described in detail as follows:

[0087] S101. Collect the basic data of the low-voltage reactive power compensation equipment. The basic data includes voltage, power factor, active load, reactive load, active power on the low-voltage side of the distribution transformer, reactive power on the low-voltage side of the distribution transformer, rated capacity of shunt capacitor compensation, rated capacity of split capacitor compensation, and abnormal voltage duration.

[0088] By collecting this basic data, the operation of the low-voltage reactive power compensation equipment can be comprehensively understood. These data are the basis for subsequent evaluation and decision-making. By collecting the key operation parameters of the equipment, the current state of the equipment can be comprehensively understood, which is conducive to discovering potential problems and optimization space of the equipment. Specifically:

[0089] Voltage: Reflects the stability of the power grid and the operating voltage level of the equipment.

[0090] Power factor: Measures the efficiency of the equipment in using electric energy. A low power factor means waste of electric energy.

[0091] Active load: Represents the power actually consumed by the equipment and is an important indicator for evaluating the load condition of the equipment.

[0092] Reactive load on the low-voltage side of the distribution transformer: Reflects the demand for reactive power in the power grid and is crucial for evaluating the effect of reactive power compensation;

[0093] Active power on the low-voltage side of the distribution transformer: Represents the actual power output on the low-voltage side of the transformer;

[0094] Reactive power: Represents the flow of reactive power in the power grid and is closely related to the power factor;

[0095] Rated capacity of the shunt capacitor and rated capacity of the series capacitor: Reflect the compensation ability of the reactive power compensation equipment;

[0096] Abnormal voltage duration: An important indicator for evaluating voltage stability. Prolonged voltage anomalies may damage equipment.

[0097] S102. Determine the evaluation indicators based on the basic data;

[0098] Through the processing and analysis of the basic data, evaluation indicators that can reflect the operating status of the equipment can be extracted. These indicators include the qualified rate of the power factor, the efficiency of reactive power compensation, the proportion of voltage anomalies, etc. By converting the original data into an operable evaluation standard, it is convenient to quantitatively evaluate the equipment performance. Through the evaluation indicators, the operating status of the equipment can be judged more scientifically.

[0099] In some embodiments, the evaluation indicators include: power factor, compensation status, matching rate, voltage qualification rate, asymmetry degree, and the health status of the low-voltage reactive power compensation equipment;

[0100] Determine the power factor based on the active power and reactive power on the low-voltage side of the distribution transformer;

[0101] Determine the compensation status based on the power factor, severity threshold, and rated capacity of the distribution transformer;

[0102] Determine the matching rate based on the rated capacity of the shunt capacitor and the rated capacity of the series capacitor;

[0103] Determine the voltage qualification rate based on the abnormal voltage duration;

[0104] Determine the asymmetry degree based on the active load and reactive load;

[0105] Determine the health status of the low-voltage reactive power compensation equipment based on the power factor.

[0106] Specifically, in the face of the error problems existing in the measurement data of the three-phase power factor on the low-voltage side of the distribution transformer, in the process of calculating the performance indicators of this solution, these possibly deviated measured values are not directly used. Instead, a theoretical calculation method is adopted to determine the power factor. By analyzing the three-phase active load and reactive load data collected from the low-voltage side of the distribution transformer, the active power and reactive power of the three phases on the low-voltage side of the distribution transformer after the reactive power compensation device is put into or cut off are deduced. This method can effectively reduce the influence of measurement errors on the calculation result of the power factor and improve the accuracy of power factor calculation.

[0107] In some embodiments, the power factor is determined according to the active power on the low-voltage side of the distribution transformer and the reactive power on the low-voltage side of the distribution transformer, specifically including:

[0108] The power factor is determined according to the following formula:

[0109]

[0110] where, cosA 1 , cosB 1 and cosC 1 are the power factors of phase A, phase B, and phase C on the low-voltage side of the distribution transformer of the low-voltage reactive power compensation equipment respectively, P a , P b , P c are the active powers of phase A, phase B, and phase C on the low-voltage side of the distribution transformer of the low-voltage reactive power compensation equipment respectively, Q a , Q b , Q c are the reactive powers of phase A, phase B, and phase C on the low-voltage side of the distribution transformer of the low-voltage reactive power compensation equipment respectively.

[0111] Preferably, due to the inherent non-negative characteristic of the power factor, it is impossible to judge whether the three phases on the low-voltage side of the distribution transformer are in under-compensation or over-compensation state only by it in reality. In order to clearly distinguish these two situations, this solution also makes a special treatment on the power factor to realize the correction of the power factor:

[0112]

[0113] After this treatment, the power factor can reflect the compensation state: if the processed power factor shows a negative value, then this indicates that the corresponding phase is currently in an over-compensation state. This method provides an effective mechanism to identify and distinguish the under-compensation and over-compensation states.

[0114] When performing state evaluation, in order to distinguish between mild and severe under-compensation or over-compensation situations, this application also introduces a threshold concept demp to determine the severity of compensation. Specifically, when the power factor of a certain phase exceeds 0 but is lower than 0.92, and its reactive load exceeds demp·Sn (S n (being the rated capacity of the affiliated distribution transformer), this phase is determined to be severely under-compensated; on the contrary, if the power factor is lower than 0 and the reactive power load is lower than demp·S n , this phase is determined to be severely over-compensated. This severity threshold can be adjusted according to the actual situation to more accurately define the severity of under-compensation and over-compensation, allowing the model to adjust the evaluation criteria according to specific requirements.

[0115] In some embodiments, the compensation status is determined based on the power factor, severity threshold, and rated capacity of the distribution transformer, specifically including:

[0116] When the power factor is between 0 and 0.92 and the reactive power is greater than the severity threshold, it is determined that the low-voltage reactive power compensation device is in a severely under-compensated state:

[0117] 0 < cosφ < 0.92 and Q > demp·S n

[0118] When the power factor is less than 0 and the reactive power is less than the severity threshold, it is determined that the low-voltage reactive power compensation device is in an over-compensated state:

[0119] cosφ < 0 and Q < demp·S n

[0120] Among them, S n is the rated capacity of the affiliated distribution transformer, demp is the severity threshold, Q is the reactive power load, and cosφ is the power factor of a certain phase of the low-voltage reactive power compensation device.

[0121] In some embodiments, the matching rate is determined based on the rated capacity of the common compensation capacitor and the rated capacity of the split compensation capacitor, specifically including:

[0122] The matching rate is determined according to the following formula:

[0123]

[0124] Among them, Q gh1 , Q gh2 ,..., Q gh5 are the rated capacities of common compensation capacitor 1, common compensation capacitor 2, common compensation capacitor 3, common compensation capacitor 4, and common compensation capacitor 5 respectively, Q gh1 , Q gh2 are the rated capacities of split compensation capacitor 1 and split compensation capacitor 2 respectively, S n is the capacity of the affiliated low-voltage reactive power compensation device, and C s is the matching rate.

[0125] Specifically, C sThe higher it is, the larger the capacity of the distribution transformer low-voltage reactive power compensation equipment accounts for the capacity of the affiliated distribution transformer.

[0126] Preferably, in the actual low-voltage distribution network, due to the long line distance between the low-voltage distribution transformer and the user end, the voltage drop from the distribution transformer to the user end is relatively significant. Combining with long-term engineering practice experience, the upper voltage limit of this application is set to 1.1U N .

[0127] In some embodiments, the voltage qualification rate is determined according to the abnormal voltage duration, which specifically includes:

[0128] Determining the voltage deviation rate according to the abnormal voltage duration;

[0129] The voltage deviation rate includes the low voltage rate and the high voltage rate, and their calculation formulas are as follows:

[0130]

[0131] Among them, V lT is the duration of the low voltage on the low-voltage side of the distribution transformer of the low-voltage reactive power compensation equipment within a day, V hT is the duration of the high voltage on the low-voltage side of the distribution transformer of the low-voltage reactive power compensation equipment within a day, N is the total number of moments, V l is the low voltage rate, V h is the high voltage rate;

[0132] Determining the voltage qualification rate according to the voltage deviation rate:

[0133] V q = 1 - V l - V h

[0134] Among them, V q is the voltage qualification rate, V l is the low voltage rate, V h is the high voltage rate.

[0135] Specifically, the low voltage rate V l reflects the proportion of moments when the voltage is lower than the normal range within a day. The higher the low voltage rate, the more moments the voltage is too low, which may affect the normal operation of the equipment and the stability of the power supply. The high voltage rate V h reflects the proportion of moments when the voltage is higher than the normal range within a day. The higher the high voltage rate, the more moments the voltage is too high, which may cause equipment overload or damage. The voltage qualification rate reflects the proportion of moments when the voltage is within the normal range within a day. The higher the voltage qualification rate, the more moments the voltage is within the normal range, and the more stable the operation of the power system.

[0136] In some embodiments, the asymmetry degree is determined according to the active load and the reactive load, specifically including:

[0137] Determine the maximum asymmetry degree P of the active load according to the following formula ubmax :

[0138]

[0139] Determine the average asymmetry degree P of the active load according to the following formula ubav :

[0140]

[0141] Determine the maximum asymmetry degree Q of the reactive load according to the following formula ubmax :

[0142]

[0143] Determine the average asymmetry degree Q of the reactive load according to the following formula ubav :

[0144]

[0145] wherein, P ubmax is the maximum asymmetry degree of the active load, P ubav is the average asymmetry degree of the active load, Q ubmax is the maximum asymmetry degree of the reactive load, Q ubav is the average asymmetry degree of the reactive load, P ak , P bk , P ck are the active loads of the a-phase, b-phase and c-phase of the low-voltage side of the distribution transformer of the low-voltage reactive power compensation device respectively, Q ak , Q bk , Q ck are the reactive loads of the a-phase, b-phase and c-phase of the low-voltage side of the distribution transformer of the low-voltage reactive power compensation device respectively, S n is the capacity of the affiliated distribution transformer, and N is the total number of moments;

[0146] Determine the asymmetry degree according to the maximum asymmetry degree P of the active load ubmax , the average asymmetry degree P of the active load ubav , the maximum asymmetry degree Q of the reactive load ubmax and the average asymmetry degree Q of the reactive load ubav .

[0147] Specifically, the maximum asymmetry degree P of the active load ubmax and the maximum asymmetry degree Q of the reactive load ubmaxIt reflects the maximum unbalance of three-phase active load and reactive load within a day. The larger the value, the more serious the three-phase load unbalance. The average asymmetry degree P of the active load ubav and the average asymmetry degree Q of the reactive load ubav can also effectively reflect the average unbalance of three-phase active load and reactive load within a day. The larger the value, the more serious the three-phase load unbalance.

[0148] In some embodiments, determining the health of the low-voltage reactive power compensation device according to the power factor specifically includes:

[0149] Calculating the mean value cos mean and the standard deviation cos std of the power factor;

[0150] Obtaining the mutual information i;

[0151] Determining the health of the low-voltage reactive power compensation device according to the mean value cos mean, the standard deviation cos std and the mutual information i:

[0152]

[0153] where cos mean is the mean value of the power factor, cos std is the standard deviation of the power factor, i is the mutual information, and h is the health of the low-voltage reactive power compensation device.

[0154] The larger the value of the device health h, the better the device operation state and the more ideal the reactive power compensation effect. If the health value is relatively low, it may be necessary to maintain or optimize the device. By regularly calculating the device health, potential problems of the device can be detected in time, faults can be prevented, and the stable operation of the power system can be ensured.

[0155] The evaluation index system constructed by several evaluation indexes in the solution of this application has high flexibility and universality, and can be widely applied to the calculation requirements in different fields. This system can provide effective evaluation and optimization solutions in the power industry and other occasions where reactive power compensation is required.

[0156] S103. Determine the operation state of the low-voltage reactive power compensation device according to the evaluation index.

[0157] Judge the operation state of the low-voltage reactive power compensation device by using the evaluation index. In this way, the operation condition of the device can be accurately grasped, abnormalities can be discovered in time, and a basis can be provided for device maintenance, fault troubleshooting and performance optimization. For example, if the qualified rate of the power factor is high and the reactive power compensation efficiency is high, it can be considered that the device operation state is good; on the contrary, if the abnormal voltage ratio is high or the reactive power compensation efficiency is low, it may be necessary to further check and repair the device.

[0158] In some embodiments, determining the operation state of the low-voltage reactive power compensation device according to the evaluation index specifically includes:

[0159] Establish a comprehensive evaluation model for the status of low-voltage reactive power compensation equipment;

[0160] Input the evaluation indexes into the comprehensive evaluation model for the status of low-voltage reactive power compensation equipment to obtain the output results;

[0161] Evaluate the operation status of the low-voltage reactive power compensation equipment according to the output results.

[0162] Preferably, the output results include the equipment status level and the cause of the fault.

[0163] Specifically, the equipment status levels include:

[0164] (1) Normal state: The equipment operates normally and all indexes are within the reasonable ranges;

[0165] (2) Abnormal: The equipment has minor problems and needs attention and monitoring;

[0166] (3) Seriously abnormal: The equipment has serious problems and needs immediate repair or replacement.

[0167] In some embodiments, inputting the evaluation indexes into the comprehensive evaluation model for the status of low-voltage reactive power compensation equipment to obtain the output results further includes:

[0168] Set the corresponding normal threshold ranges for 6 indexes (power factor, compensation status, matching rate, voltage qualification rate, asymmetry degree, and the health degree of low-voltage reactive power compensation equipment) respectively;

[0169] When all of the above 6 indexes meet the normal threshold ranges, it is determined that the low-voltage reactive power compensation equipment is in the normal state;

[0170] When the first part of the above 6 indexes does not meet the normal threshold ranges, it is determined that the low-voltage reactive power compensation equipment is in the abnormal state;

[0171] When the second part of the above 6 indexes does not meet the normal threshold ranges, it is determined that the low-voltage reactive power compensation equipment is in the abnormal state;

[0172] Specifically, the types and quantities of the indexes included in the first part of the indexes and the second part of the indexes can be adjusted according to the actual application scenarios.

[0173] Specifically, according to the evaluation indexes, analyze the possible causes of equipment abnormalities, and the causes of the faults include:

[0174] (1) Too low power factor: It may be that the equipment configuration is unreasonable or the load is too heavy;

[0175] (2) Too low voltage qualification rate: It may be that the equipment has a fault or the grid voltage is unstable;

[0176] (3) Excessive asymmetry: It may be due to equipment failure or unbalanced three-phase loads.

[0177] (4) Low equipment health: It may be due to equipment aging or faults.

[0178] Through precise evaluation and optimized management, the operating efficiency of the power system has been effectively improved. The output results and fault causes can guide the adjustment of the power system in terms of reactive power compensation, which is conducive to realizing real-time monitoring and adjustment of the operating state of equipment.

[0179] This patent realizes precise evaluation of the operating state of low-voltage reactive power compensation equipment by constructing a comprehensive evaluation model for the state of low-voltage reactive power compensation equipment. This model comprehensively considers quantified indicators to comprehensively evaluate the state of reactive power compensation equipment, which not only includes the immediate operating state of the equipment but also covers multi-dimensional analysis of the compensation effect, and can comprehensively reflect the operating state and compensation effect of the device, thereby improving the scientificity and accuracy of the evaluation. It can delicately capture the subtle changes in equipment operation, thus providing more accurate evaluation results. This refined evaluation method not only improves the accuracy of the evaluation work but also provides more reliable data support for the operation management of equipment.

[0180] In some embodiments, the operating state of low-voltage reactive power compensation equipment is determined according to evaluation indicators, specifically including:

[0181] 1. Preliminary evaluation: According to evaluation indicators, such as power factor, voltage qualification rate, etc., the equipment operating state is divided into several levels, such as normal, abnormal, and severely abnormal.

[0182] 2. Introduce fuzzy logic evaluation:

[0183] Fuzzy membership degree: The evaluation indicators are divided into 3 fuzzy sets: low fuzzy set, medium fuzzy set, and high fuzzy set, and the membership degree of the equipment state to each set is calculated;

[0184] Set according to the membership degree and the rule base to infer the comprehensive state of the equipment: "Equipment state is good", "Equipment has abnormalities".

[0185] 3. Introduce system evaluation:

[0186] Establish a knowledge base for equipment state evaluation, including equipment fault diagnosis rules and equipment maintenance strategies;

[0187] According to the evaluation indicators and the knowledge base, infer the possible faults and solutions of the equipment.

[0188] 4. Set up an alarm system:

[0189] When the device is abnormal, an alarm is issued in a timely manner, and the corresponding fault diagnosis is output to remind the operation and maintenance personnel to take actions.

[0190] In summary, the solution of this application can comprehensively and objectively evaluate the operation status of the low-voltage reactive power compensation device by collecting and analyzing the basic data of the low-voltage reactive power compensation device, and finally achieve an accurate judgment of the operation status of the low-voltage reactive power compensation device. This will help improve the operation efficiency of the power system, reduce energy consumption, and ensure the stability and reliability of power supply. At the same time, it also provides a scientific basis for equipment maintenance and management.

[0191] This application also proposes a low-voltage reactive power compensation device status evaluation system, which includes: a data acquisition unit, a judgment index determination unit, and a low-voltage reactive power compensation device status evaluation unit;

[0192] The data acquisition unit is used to collect the basic data of the low-voltage reactive power compensation device, and the basic data includes voltage, power factor, active load, reactive load, active power on the low-voltage side of the distribution transformer, reactive power on the low-voltage side of the distribution transformer, rated capacity of the common compensation capacitor, rated capacity of the split compensation capacitor, and abnormal voltage duration;

[0193] The judgment index determination unit is used to determine the evaluation index according to the basic data;

[0194] The low-voltage reactive power compensation device status evaluation unit is used to determine the operation status of the low-voltage reactive power compensation device according to the evaluation index.

[0195] Figure 2 The internal structure diagram of a computer device in an embodiment is shown. This computer device can specifically be a terminal or a server. As Figure 2 shown, this computer device includes a processor, a memory, and a network interface connected through a system bus. Among them, the memory includes a non-volatile storage medium and an internal memory. The non-volatile storage medium of this computer device stores an operating system and can also store a computer program. When the computer program is executed by the processor, the processor can implement the age recognition method. The internal memory can also store a computer program. When the computer program is executed by the processor, the processor can execute the age recognition method. Those skilled in the art can understand that Figure 2 the structure shown in is only a block diagram of some structures related to the solution of this application, and does not constitute a limitation on the computer device to which the solution of this application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine some components, or have different component arrangements.

[0196] This application also proposes a readable storage medium, storing a computer program, which when executed by a processor, causes the processor to perform the following steps:

[0197] Collect the basic data of the low-voltage reactive power compensation device, where the basic data includes voltage, power factor, active load, reactive load, active power on the low-voltage side of the distribution transformer, reactive power on the low-voltage side of the distribution transformer, rated capacity of the common compensation capacitor, rated capacity of the split compensation capacitor, and abnormal voltage duration;

[0198] Determine the evaluation index according to the basic data;

[0199] Determine the operating state of the low-voltage reactive power compensation device according to the evaluation index.

[0200] This application also proposes a computer device, including a memory and a processor. The memory stores a computer program, and the computer program is executed by the processor to perform the following steps:

[0201] Collect the basic data of the low-voltage reactive power compensation device, where the basic data includes voltage, power factor, active load, reactive load, active power on the low-voltage side of the distribution transformer, reactive power on the low-voltage side of the distribution transformer, rated capacity of the common compensation capacitor, rated capacity of the split compensation capacitor, and abnormal voltage duration;

[0202] Determine the evaluation index according to the basic data;

[0203] Determine the operating state of the low-voltage reactive power compensation device according to the evaluation index.

[0204] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to the memory, storage, database, or other media used in the various embodiments provided in this application can include non-volatile and / or volatile memories. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0205] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0206] The above-described embodiments merely represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. The above-disclosed are only the preferred embodiments of the present invention, and of course, the scope of the present invention cannot be limited thereby. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. A method for evaluating the state of a low-voltage reactive power compensation device, characterized in that: The method comprises: Collect basic data of low-voltage reactive power compensation equipment, including voltage, power factor, active load, reactive load, active power on the low-voltage side of the distribution transformer, reactive power on the low-voltage side of the distribution transformer, rated capacity of the common compensation capacitor, rated capacity of the separate compensation capacitor, and duration of abnormal voltage; Determining evaluation indicators based on the basic data; The operating status of the low-voltage reactive power compensation equipment is determined according to the evaluation index.

2. The low-voltage reactive power compensation equipment status assessment method according to claim 1, characterized in that: The evaluation indicators include: power factor, compensation status, matching rate, voltage qualification rate, asymmetry and health of low-voltage reactive power compensation equipment; Determining the power factor according to the active power on the low-voltage side of the distribution transformer and the reactive power on the low-voltage side of the distribution transformer; determining a compensation state according to the power factor, the severity threshold and the rated capacity of the distribution transformer; Determine the matching rate according to the rated capacity of the common compensation capacitor and the rated capacity of the separate compensation capacitor; Determining a voltage qualification rate according to the abnormal voltage duration; determining asymmetry according to the active load and the reactive load; The health status of the low-voltage reactive power compensation equipment is determined according to the power factor.

3. The low-voltage reactive power compensation equipment status assessment method according to claim 2, characterized in that: Determining the power factor according to the active power on the low-voltage side of the distribution transformer and the reactive power on the low-voltage side of the distribution transformer specifically includes: Determine the power factor using the following formula: Among them, cosA1, cosB1 and cosC1 are the power factors of phase A, phase B and phase C on the low-voltage side of the distribution transformer of the low-voltage reactive power compensation equipment respectively; P a , P b , P c They are respectively the active power of phase A, phase B and phase C of the low-voltage side of the distribution transformer of the low-voltage reactive compensation equipment; Q a , Q b , Q c They are the reactive power of phase A, phase B and phase C on the low-voltage side of the distribution transformer of the low-voltage reactive compensation equipment.

4. The low-voltage reactive power compensation equipment status assessment method according to claim 2, characterized in that: The determining of the compensation state according to the power factor, the severity threshold and the rated capacity of the distribution transformer specifically includes: When the power factor is between 0 and 0.92 and the reactive power is greater than the severity threshold, it is determined that the low-voltage reactive power compensation device is in a severe under-compensation state: 0 < cosφ < 0.92 and Q > demp - S n When the power factor is less than 0 and the reactive power is less than the severity threshold, it is determined that the low-voltage reactive power compensation device is in an over-compensation state: cosφ<0 and Q <demp·S n Among them, S n is the rated capacity of the distribution transformer, demp is the severity threshold, Q is the reactive load, and cosφ is the power factor of a certain phase of the low-voltage reactive compensation equipment.

5. The low-voltage reactive power compensation equipment status assessment method according to claim 2, characterized in that: The determining of the matching rate according to the rated capacity of the common compensation capacitor and the rated capacity of the separate compensation capacitor specifically includes: The match rate is determined according to the following formula: Among them, Q gh1 , Q gh2 ,...,Q gh5 are the rated capacities of the common compensation capacitor 1, the common compensation capacitor 2, the common compensation capacitor 3, the common compensation capacitor 4 and the common compensation capacitor 5, respectively, Q gh1 , Q gh2 are the rated capacities of the sub-compensation capacitor 1 and the sub-compensation capacitor 2, Sn is the capacity of the low-voltage reactive power compensation equipment, C s is the matching rate.

6. The method for evaluating the state of low-voltage reactive power compensation equipment according to claim 2, characterized in that: The determining of the voltage qualification rate according to the voltage abnormal duration specifically includes: Determining a voltage deviation rate according to the duration of the abnormal voltage; The voltage deviation rate includes the voltage low rate and the voltage high rate, and the calculation formula is as follows: Among them, V lT V is the duration of low voltage side voltage of the distribution transformer of low voltage reactive power compensation equipment in a day. hT is the duration of high voltage on the low-voltage side of the distribution transformer of the low-voltage reactive compensation equipment within a day, N is the total number of moments, V l is the voltage low rate, V h is the voltage high rate; Determine the voltage qualification rate according to the voltage deviation rate: V q =1-V l -V h Among them, V q is the voltage qualification rate, V l is the voltage low rate, V h is the voltage high rate.

7. The low-voltage reactive power compensation equipment status assessment method according to claim 2, characterized in that: The determining of the asymmetry according to the active load and the reactive load specifically includes: Determine the maximum asymmetry of active load P according to the following formula: ubmax : Determine the average asymmetry of active load P according to the following formula: ubav : Determine the maximum asymmetry of reactive load Q according to the following formula ubmax : Determine the average asymmetry of reactive load Q according to the following formula ubav : Among them, P ubmax is the maximum asymmetry of active load, P ubav is the average asymmetry of active load, Q ubmax is the maximum asymmetry of reactive load, Q ubav is the average asymmetry of reactive load, P ak , P bk , P ck are the active loads of phases a, b and c on the low-voltage side of the distribution transformer of the low-voltage reactive compensation equipment, Q ak , Q bk , Q ck are the reactive loads of phases a, b and c on the low-voltage side of the distribution transformer of the low-voltage reactive compensation equipment, respectively. n is the capacity of the distribution transformer, and N is the total number of moments; According to the maximum asymmetry of active load P ubmax , average asymmetry of active load P ubav , Maximum asymmetry of reactive load Q ubmax and the average asymmetry of reactive load Q ubav Determine the degree of asymmetry.

8. A low voltage reactive power compensation equipment status assessment system, characterized in that: The system comprises: a data acquisition unit, a judgment index determination unit and a low-voltage reactive power compensation equipment state evaluation unit; The data acquisition unit is used to collect basic data of low-voltage reactive compensation equipment, and the basic data includes voltage, power factor, active load, reactive load, active power on the low-voltage side of the distribution transformer, reactive power on the low-voltage side of the distribution transformer, rated capacity of the common compensation capacitor, rated capacity of the separate compensation capacitor, and abnormal voltage duration; The judgment index determination unit is used to determine the evaluation index according to the basic data; The low-voltage reactive compensation equipment state evaluation unit is used to determine the operating state of the low-voltage reactive compensation equipment according to the evaluation index.

9. A readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor executes the steps of the method for evaluating the state of a low-voltage reactive compensation device as claimed in any one of claims 1 to 7.

10. A computer device comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method for evaluating the state of a low-voltage reactive compensation device as claimed in any one of claims 1 to 7.

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