CN-122017333-A - Abnormality monitoring and alarming method, system and device for energy storage converter

CN122017333ACN 122017333 ACN122017333 ACN 122017333ACN-122017333-A

Abstract

The invention belongs to the technical field of monitoring of energy storage converters, and particularly relates to an abnormality monitoring and alarming method, system and device of an energy storage converter, which comprise the following steps of S1, obtaining operation parameters of the converter; S2, calculating a power balance difference based on total power and loss models of alternating current and direct current sides, judging system abnormality if a threshold value is exceeded, further calculating deviation degree of expected current and actual current of each battery cluster, locating a specific abnormal battery cluster and alarming, S3, screening and sequencing according to safety constraint and comprehensive priority scores from healthy battery clusters to form a priority standby sequence, S4, determining power to be transferred, and intelligently reassigning power to the healthy battery clusters according to the sequence and battery safety margin. The invention realizes the accurate positioning and intelligent power reconstruction of the abnormal battery cluster, and improves the accuracy and the operation usability of the fault diagnosis of the energy storage system.

Inventors

LIU DI
LI ZHUANG
LI RAN
WU SHILONG
WANG BENCHAO
XU YONGZHEN
FAN HONGJUN
HE RUIPENG
LIU LIN
LIU TIE
WANG ZHENHU

Assignees

山东泰开储能科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260211

Claims (10)

1. The abnormality monitoring and alarming method for the energy storage converter is characterized by comprising the following steps of: S1, acquiring a charging and discharging state, direct current, direct voltage, alternating voltage and alternating current of an energy storage converter; S2, calculating total power of an alternating current side based on alternating voltage and alternating current of the energy storage converter, calculating total power of a direct current side based on direct current voltage and direct current, estimating power loss through a preset energy storage converter loss model, calculating a power balance difference index based on the total power of the alternating current side, the total power of the direct current side and the power loss, and judging that the current energy storage converter is an abnormal energy storage converter when the power balance difference index exceeds a first threshold; Calculating expected direct current of each battery according to total power of a direct current side of the abnormal energy storage converter and voltage of each battery, calculating direct current deviation degree of each battery based on the expected direct current of each battery, judging the battery which is deviated from the expected direct current unidirectionally within continuous m time windows as the abnormal battery and giving an alarm, wherein the absolute value of the direct current deviation degree exceeds a second threshold; S3, screening out batteries which meet the first-stage safety constraint condition from other batteries except for abnormal batteries in the energy storage converter to form a primary standby pool, calculating a comprehensive priority score for each battery in the primary standby pool, and sorting the batteries in the primary standby pool in a descending order according to the comprehensive priority score to form a priority standby sequence; S4, determining power to be transferred from the abnormal battery based on the power balance difference index and the DC deviation degree, and repeating the process until the power to be transferred is completely distributed or the priority standby sequence is traversed according to the order of the priority standby sequence, wherein the power increment distributed to the current standby battery does not exceed the maximum safe increasable power calculated based on the real-time state.
2. The abnormality monitoring and alarming method of the energy storage converter according to claim 1, wherein in the step S2, power loss is estimated through a preset energy storage converter loss model, specifically, measured total loss of the energy storage converter is measured at different load points, theoretical loss is calculated based on conduction loss, switching loss and auxiliary loss, the theoretical loss and the measured total loss are compared and calibrated, a two-dimensional table look-up is formed, and the power loss is obtained through real-time table look-up according to the total power of the current alternating current side and the total power of the direct current side.
3. The abnormality monitoring and alarming method of the energy storage converter according to claim 1, wherein in the step S2, a power balance difference index is calculated based on total power of an alternating current side, total power of a direct current side and power loss, specifically, when the energy storage converter is in a discharging state, the total power of the alternating current side plus the power loss minus the absolute value of the total power of the direct current side, and the root mean square in a sliding time window is the power balance difference index; When the energy storage converter is in a discharging state, the absolute value obtained by subtracting the total power of the alternating current side from the total power added by the power loss of the direct current side is used as a power balance difference index.
4. The abnormality monitoring and alarming method of an energy storage converter according to claim 1, wherein in S2, the expected dc current of each battery is calculated according to the current total power and each battery voltage: , Wherein, the For the total power on the dc side, For the dc voltage of the i-th cell, The battery health of the i-th battery.
5. The abnormality monitoring and alarming method of an energy storage converter according to claim 1, wherein in S2, based on expected currents of each battery, a dc current deviation degree of each battery is calculated: , wherein, In the form of a direct current (dc) current, For a desired dc current of the i-th cell, Is the allowable maximum charge-discharge current of the i-th battery.
6. The abnormality monitoring and alarming method for the energy storage converter according to claim 1, wherein the first-stage safety constraint condition in the step S3 includes that the state of charge of the battery is within a preset safety window, the direct current of the battery is smaller than the expected direct current, the state of health of the battery is higher than a preset threshold, and the temperature of the battery is within a preset normal range.
7. The abnormality monitoring and alarming method of an energy storage converter according to claim 1, wherein the calculation formula of the comprehensive priority score in S3 is: Wherein, the In the form of a state of charge, In the state of health of the patient, For a real-time margin, For the abnormal proportion, w1, w2, w3 and w4 are preset weight coefficients and are positive numbers.
8. The abnormality monitoring and alarming method of an energy storage converter according to claim 1, wherein in S4, based on a power balance difference index and a current deviation degree, determining power to be transferred from an abnormal battery, specifically, if a ratio of the power balance difference index exceeding a first threshold is smaller than a first ratio and a ratio of the direct current deviation degree exceeding a second threshold is smaller than a second ratio, setting the power to be transferred as the power balance difference index; If the proportion of the power balance difference index exceeding the first threshold value is larger than the third proportion, setting the power to be transferred as the power before the fault of the abnormal battery; If the ratio of the power balance difference index exceeding the first threshold is between the first ratio and the second ratio, the power to be transferred is the product of the power before the fault of the abnormal battery and the related ratio coefficient.
9. An abnormality monitoring alarm system for an energy storage converter, for implementing an abnormality monitoring alarm method for an energy storage converter according to any one of claims 1 to 8, comprising a data acquisition module for acquiring a charge-discharge state, a direct current voltage, an alternating current voltage, and an alternating current of the energy storage converter; The abnormality judging module is used for calculating total power of an alternating current side based on alternating voltage and alternating current of the energy storage converter, calculating total power of a direct current side based on direct current voltage and direct current, estimating power loss through a preset energy storage converter loss model, calculating a power balance difference index based on the total power of the alternating current side, the total power of the direct current side and the power loss, and judging that the current energy storage converter is an abnormal energy storage converter when the power balance difference index exceeds a first threshold value; Calculating expected direct current of each battery according to total power of a direct current side of the abnormal energy storage converter and voltage of each battery, calculating direct current deviation degree of each battery based on the expected direct current of each battery, judging the battery which is deviated from the expected direct current unidirectionally within continuous m time windows as the abnormal battery and giving an alarm, wherein the absolute value of the direct current deviation degree exceeds a second threshold; the priority standby sequence calculation module is used for screening out batteries which meet the first-level safety constraint condition from other batteries except for abnormal batteries in the energy storage converter to form a primary standby pool, calculating a comprehensive priority score for each battery in the primary standby pool, and sorting the batteries in the primary standby pool in descending order according to the comprehensive priority score to form a priority standby sequence; The distribution module determines the power to be transferred, which needs to be transferred from the abnormal battery, based on the power balance difference index and the direct current deviation degree, and the power increment distributed to the current standby battery does not exceed the maximum safe increasable power calculated based on the real-time state according to the sequence of the priority standby sequence, and repeats the process until the power to be transferred is completely distributed or the priority standby sequence is traversed.
10. An abnormality monitoring and alarming device for an energy storage converter, comprising a processor and a memory, wherein the processor implements an abnormality monitoring and alarming method for an energy storage converter according to any one of claims 1 to 8 when executing a computer program stored in the memory.

Description

Abnormality monitoring and alarming method, system and device for energy storage converter Technical Field The invention belongs to the technical field of monitoring of energy storage converters, and particularly relates to an abnormality monitoring and alarming method, system and device of an energy storage converter. Background The energy storage converter is used as a core power conversion unit of the electrochemical energy storage system, and the operation reliability of the energy storage converter directly influences the safety and efficiency of the whole energy storage power station. Energy storage converters are typically powered and stored in parallel by multiple batteries to achieve high capacity and high power output. At present, the abnormality monitoring method for the energy storage converter mainly has the following technical defects: the existing method is mainly based on total voltage and total current threshold values of an alternating current side or a direct current side to alarm, such as direct current overvoltage and alternating current overcurrent, but can not accurately position which of a plurality of batteries is an abnormal source, so that alarm delay and even missing report are caused, and great difficulty is brought to fault detection. Most methods adopt fixed current and voltage thresholds, and cannot fully consider the physical characteristics of the energy storage converter, such as different energy flow directions and current directions under different charging and discharging working conditions, and the sensitivity is insufficient under specific working conditions. After the alarm, manual intervention is usually relied on, or simple shutdown protection is executed, so that the usability of the system is interrupted, the capacity is wasted, and the whole energy storage converter is possibly shut down due to single-point failure, so that the loss is large. Disclosure of Invention The invention aims to provide an abnormality monitoring and alarming method, system and device for an energy storage converter. An abnormality monitoring and alarming method for an energy storage converter comprises the following steps: S1, acquiring a charging and discharging state, direct current, direct voltage, alternating voltage and alternating current of an energy storage converter; S2, calculating total power of an alternating current side based on alternating voltage and alternating current of the energy storage converter, calculating total power of a direct current side based on direct current voltage and direct current, estimating power loss through a preset energy storage converter loss model, calculating a power balance difference index based on the total power of the alternating current side, the total power of the direct current side and the power loss, and judging that the current energy storage converter is an abnormal energy storage converter when the power balance difference index exceeds a first threshold; Calculating expected direct current of each battery according to total power of a direct current side of the abnormal energy storage converter and voltage of each battery, calculating direct current deviation degree of each battery based on the expected direct current of each battery, judging the battery which is deviated from the expected direct current unidirectionally within continuous m time windows as the abnormal battery and giving an alarm, wherein the absolute value of the direct current deviation degree exceeds a second threshold; S3, screening out batteries which meet the first-stage safety constraint condition from other batteries except for abnormal batteries in the energy storage converter to form a primary standby pool, calculating a comprehensive priority score for each battery in the primary standby pool, and sorting the batteries in the primary standby pool in a descending order according to the comprehensive priority score to form a priority standby sequence; S4, determining power to be transferred from the abnormal battery based on the power balance difference index and the DC deviation degree, and repeating the process until the power to be transferred is completely distributed or the priority standby sequence is traversed according to the order of the priority standby sequence, wherein the power increment distributed to the current standby battery does not exceed the maximum safe increasable power calculated based on the real-time state. And S2, estimating power loss through a preset energy storage converter loss model, wherein the specific operation is that the measured total loss of the energy storage converter is measured at different load points, theoretical loss is calculated based on conduction loss, switching loss and auxiliary loss, the theoretical loss and the measured total loss are compared and calibrated to form a two-dimensional table lookup, and the power loss is obtained by real-time table lookup according to the total power of the current alt