CN110620369A

CN110620369A - Overvoltage fault diagnosis and isolation method for aviation power generation system

Info

Publication number: CN110620369A
Application number: CN201910761395.XA
Authority: CN
Inventors: 张桂芳; 王智慧; 李骏; 王晓红; 陈复盼
Original assignee: Shaanxi Aero Electric Co Ltd
Current assignee: Shaanxi Aero Electric Co Ltd
Priority date: 2019-08-18
Filing date: 2019-08-18
Publication date: 2019-12-27
Anticipated expiration: 2039-08-18
Also published as: CN110620369B

Abstract

The invention provides an overvoltage fault diagnosis and isolation method for an aviation power generation system, which is used for optimizing and improving the conventional fault detection, fault diagnosis and fault isolation methods. According to the characteristics of a power supply system, various operating conditions and scenes of the power supply system are identified and analyzed in one or more information combination modes, fault discrimination and hazard grade analysis in various modes are established, a fault false alarm and a real overvoltage fault are judged by taking the completion of a power supply task as a guide, targeted alarm processing and protection are carried out, the power supply reliability and safety are improved, and the fault isolation rate and the testability are improved.

Description

Overvoltage fault diagnosis and isolation method for aviation power generation system

Technical Field

The invention belongs to the technical field of aviation electrical design, and relates to an overvoltage fault diagnosis and isolation method for an aviation power generation system.

Background

At present, with the development of multi-electric aircraft, the safety and reliability of the power supply system of the multi-electric aircraft are generally concerned, but the power supply system is very complex and plays a very important role in the whole flight or attack, and the fault and failure of the power supply can cause very serious consequences, so the research on the fault diagnosis of the aviation power supply system is particularly important. If the system fails to be checked and corrected in time, the fault easily affects the state and function of the system, and a safety accident is caused seriously.

The application of fault diagnosis technology to the airplane power system is an important method for ensuring system safety, is an important guarantee for improving system safety and reliability, and is a direct factor influencing flight safety and fighting capacity. The failure of the power supply system is effectively eliminated, so that the fighting capacity of the airplane can be improved, and the completion of the flight mission is further ensured. However, the power supply system is complex, the failure thereof is also complex, and the cause of the failure is complicated, so that it is necessary to conduct an intensive study on the failure diagnosis technology.

Based on the existing overvoltage fault diagnosis technology, the single fault mode of the power generation system can be accurately judged, and the fault information of the power generation system is transmitted to the upper computer. In the actual test and outfield test flight processes, multiple fault modes often occur, the faults are mutually linked and occur concomitantly, most faults are not caused by the abnormal power generation function of the power generation system, but due to limited detection information, the multivariable coupling characteristic of the power generation system and incomplete fault judgment logic, the accidents of power system grid disconnection caused by false alarm, error protection and misoperation often occur, and the task reliability of the power system is seriously influenced.

At present, an overvoltage fault diagnosis method of an aviation power generation system is simple, judgment is carried out according to single important system state quantity mainly based on an internal BIT self-detection technology, the characteristics of multivariable, nonlinearity and strong coupling of a power generation system and an electrical load are not considered by utilizing simple mechanisms and logic relations among variables, the overall view and task reliability of an onboard power grid are not established, and various operation working conditions and various fault modes of a power supply system cannot be accurately and comprehensively judged. For a power supply network with a complex cross-linking relation, software fault diagnosis logic is simple, fault isolation is inaccurate, and coordination between fault grading evaluation, fault accurate isolation, decision-making power generation system alarm processing and execution protection cannot be realized through various data and professional experience.

Disclosure of Invention

The invention provides an overvoltage fault diagnosis and isolation method for an aviation power generation system, which aims to solve the problems of network withdrawal caused by false alarm misoperation and difficulty in external field fault location caused by inaccurate fault isolation when an overvoltage fault occurs in the aviation power generation system. According to the characteristics of a power supply system, various operating conditions and scenes of the power supply system are identified and analyzed in one or more information combination modes, fault discrimination and hazard grade analysis in various modes are established, fault false alarm and real overvoltage faults are judged by taking the completion of a power supply task as a guide, targeted alarm processing and protection are carried out, the power supply reliability and safety are improved, and the fault isolation rate and the testability are improved.

The technical scheme of the invention is as follows:

the method for diagnosing and isolating the overvoltage fault of the aviation power generation system is characterized by comprising the following steps: the method comprises the following steps:

the method comprises the following steps: collecting three-phase voltage values of the generator to obtain a POR three-phase voltage maximum value POR _ MAX;

step two: judging whether the POR highest phase voltage value POR _ MAX exceeds an overvoltage threshold value U, if so, setting an overvoltage fault flag, and executing a step III; otherwise, executing the step four;

step three: judging generator current IGCT, line current ILCT and permanent magnet machine rectification voltage u_TRU28VAnd u_LiCiWhether or not IGCT is satisfied at 0. ltoreq._(A,B,C)≤IGCT_{2 times load}、0≤ILCT_(A,B,C)≤ILCT_{2 times load}、u_TRU28V<ΔU₁,u_LiCi＜ΔU₂If one of the conditions is met, the overvoltage fault is considered to occur at the moment, and a fifth step is executed; if the fault conditions are not met, the fault condition is regarded as an overvoltage fault false alarm caused by sampling of the controller, the 'controller fault' is reported to the upper computer,entering the step eight; wherein the IGCT_{2 times load}At 2 times the generator current, ILCT_{2 times load}At 2 times the line current, Δ U₁And Δ U₂Is a set threshold voltage;

step four: judging whether overvoltage faults occur in the upper running period, if so, resetting the overvoltage fault mark, and executing the step eight; if not, resetting the overvoltage fault protection mark, the overvoltage fixed time delay Udelay1 and the overvoltage reverse time delay Udelay2, and simultaneously entering the step eight;

step five: judging whether the exciting current If meets If<1/2If₀，If₀The current is no-load exciting current, If yes, the exciting negative line is considered to have a short circuit to the ground, the fault is isolated to the exciting negative line, the 'exciting negative line short circuit causes overvoltage fault' is reported to the upper computer, and If not, whether the exciting current If meets the If is further judged>2If_{2 times load}，If_{2 times load}Is 2 times of excitation current, if the excitation current is satisfied, the excitation control power tube is considered to be uncontrolled at the moment, the fault is isolated to the controller, the controller fault is reported to the upper computer, and if the excitation current is not satisfied, the line current ILCT at the current fault is further judged_(Current)And line current ILCT in the absence of a fault_{(without failure)}Whether or not | ILCT is satisfied_(Current)-ILCT_{(without failure)}|>Delta I, wherein the delta I is a set line current threshold value, if the delta I is met, the fault is considered to be a fault caused by sudden abnormality of an external load end, the fault is isolated to the external load, and the 'external load causes overvoltage fault' is reported to the upper computer, otherwise, the working of the voltage regulating circuit is considered to be abnormal at the moment, the fault is isolated to the controller, and the 'controller fault' is reported to the upper computer;

in addition, whether the overvoltage reverse delay Udelay2 is reached is judged in the step, if yes, an overvoltage fault protection mark is set, and a seventh step is executed; if not, accumulating the over-pressure difference and the integral threshold, and executing a sixth step;

step six: judging whether the overvoltage fixed time delay Udelay1 is reached, if so, setting an overvoltage fault protection mark, and executing a seventh step; otherwise, increasing the delay and entering the step eight at the same time;

step seven: outputting a main contactor disconnection instruction, controlling the power generation system to quit the network, and entering the step eight;

step eight: and (6) exiting.

Advantageous effects

The invention takes the reduction of the overvoltage fault false alarm and the false operation of the power generation system and the improvement of the power supply reliability as the main points, and analyzes the power generation systems with different working conditions and different fault modes according to the multivariable coupling characteristics of the power generation system. Aiming at different fault reasons, different fault diagnosis strategies are provided according to fault harmfulness and fault characteristics, fault classification and protection priority are judged, a power generation system task is taken as guidance, and alarm processing or protection network quitting measures are taken to isolate faults. The grid disconnection accident of the power generation system caused by the false alarm fault is reduced, the power supply reliability and stability are improved, and the method has important significance for improving the performance of the power supply system of the airplane in the future.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a functional block diagram of an over-voltage fault diagnostic;

FIG. 2 over-voltage failure mode FTA analysis;

FIG. 3 is a logic block diagram of overvoltage fault handling;

fig. 4 is a logic block diagram of overvoltage fault isolation.

Detailed Description

The invention provides an overvoltage fault diagnosis and isolation method for an aviation power generation system, which optimizes and improves the overvoltage fault diagnosis (namely fault judgment, fault protection and fault isolation) software control logic on the basis of the existing hardware circuit. According to the characteristics of a power supply system, various operating conditions and scenes of the power supply system are identified and analyzed in one or more information combination modes, fault discrimination and hazard grade analysis in various modes are established, the completion of a power supply task is guided, fault false alarm and real overvoltage faults are judged, targeted alarm processing and protection are performed, the power supply reliability and safety are improved, and the fault isolation rate and the testability are improved.

The functional block diagram of the overvoltage fault diagnosis is shown in fig. 1, a controller collects three-phase voltage of a sensitive line, the three-phase voltage is sent to a DSP control circuit through an internal peak value sampling processing circuit and a bus interface circuit, a voltage sampling value is compared with an overvoltage judgment threshold through a software overvoltage monitoring module, various fault modes are integrated through an output control module, a main contactor control command is output, and connection and disconnection of a power generation system and an onboard power grid are controlled. When overvoltage is detected, the controller outputs a main contactor disconnection instruction and an excitation disconnection instruction after a certain time delay, and the power generation system is controlled to quit the network, so that the protection function is realized.

According to the fault mode, influence and hazard (FMECA) analysis of an alternating current power supply system and the combination of multiple overvoltage faults occurring in recent years on an airplane, the invention deeply analyzes the mechanism of the overvoltage faults, the reason of the overvoltage faults can be caused by one or more factors such as a generator, a controller, a load and a circuit, and an overvoltage Fault Tree (FTA) of a power generation system is established as shown in figure 2.

For each fault phenomenon in fig. 2, the fault hazard degree is evaluated to complete the system power supply task and reduce the false alarm as a guide, the fault processing and fault isolation strategies are analyzed, the fault is classified according to each fault mode characteristic, and different processing measures are taken, and the specific analysis is as follows:

a) b1, B6, B8 failure mode (field negative line to ground short): the actual exciting current reaches dozens of amperes, the exciting current sampled by the controller is small (close to zero), the output voltage at the generator end is maximum at the moment and reaches the output characteristic saturation value, all electrical equipment at the rear stage of the power generation system can be damaged, the damage range is wide, protection is required to be executed within tens of milliseconds to prevent fault amplification, and meanwhile, a voltage fault is reported to the upper computer.

b) B2 fault mode (field control switching tube damaged, fully conducting): in this case, the excitation current sampled by the controller and the actual excitation current are both large, the system output voltage is maximum, namely the saturation value and the hazard degree are the same as a), protection is also executed within tens of milliseconds, and meanwhile, a voltage fault is reported to the upper computer.

c) B3 fault mode (reference source drift of voltage regulating circuit, mean value reduction of feedback terminal): under the condition, the duty ratio of the voltage regulating circuit is increased, the voltage is increased, the exciting current is increased within the saturation voltage, the voltage is continuously applied to the electric equipment, the insulation of the equipment is damaged, the protection is carried out within one hundred milliseconds and several seconds according to the size of the collected sensitive voltage, and meanwhile, the voltage fault is reported to an upper computer.

d) B4 (bleeding circuit abnormal), B5 failure mode (sampling circuit abnormal): the method is characterized in that the sampling circuit is abnormal in function due to leakage and drift, non-real-time peak value of sampled sensitive voltage is caused, under the condition, only inaccurate voltage sampling value read by software is caused, the voltage on an actual sensitive line is normal, the power generation function of a system is normal, power supply is kept for guaranteeing flight safety and system task reliability, faults are not protected and isolated, and meanwhile, the alarm processing is carried out on an upper computer, and overvoltage faults and controller faults are reported.

e) B7 failure mode (external load exception): the overvoltage caused by the situation is mainly caused by factors such as the input or the removal of a high-power load, the conversion of a power grid power supply, the removal of a short circuit and a short circuit of the load, the starting of a motor load and the like, the dynamic time is generally from several milliseconds to several seconds, the self current protection function of a fault point at the end of the load should preferentially act at the moment, the effective isolation is carried out when the fault occurs, the overvoltage protection function of a power generation system should be matched with the upper protection level and the lower protection level of the load, and under the condition that the self protection function of the load fails and cannot be effectively isolated, the power generation system executes protection and cuts off the fault for.

The invention is further described below with reference to the accompanying drawings.

Fig. 3 is a logic block diagram of overvoltage fault processing, and it can be known from analysis in fig. 2 that, except for the overvoltage fault mode processing measures of B4 and B5 being fault alarms, the other fault modes all need to protect network withdrawal operation, so as to ensure safety of the subsequent-stage power consumption equipment. The B4 and B5 fault modes are overvoltage faults caused by sampling problems detected by the controller, other state quantities (generator current, load current, excitation positive voltage, permanent magnet machine rectification voltage and the like) of the power generation system are used for identification and judgment, and if the state quantities are normal, the overvoltage is considered to be caused by abnormal sampling of a fault phase. It belongs to false alarm, and it only reports the fault and does not protect it. The specific software control logic is as follows:

step three: judging generator current IGCT, line current ILCT and permanent magnet machine rectification voltage u_TRU28VAnd u_LiCiWhether or not IGCT is satisfied at 0. ltoreq._(A,B_,C)≤IGCT_{2 times load}、0≤ILCT_(A,B_,C)≤ILCT_{2 times load}、u_TRU28V<ΔU₁,u_LiCi＜ΔU₂If one of the conditions is met, the overvoltage fault is considered to occur at the moment, and a fifth step is executed; if the sampling result is not satisfied, the fault false alarm caused by sampling is considered at the moment, and the step eight is executed; wherein the IGCT_{2 times load}At 2 times the generator current, ILCT_{2 times load}At 2 times the line current, Δ U₁And Δ U₂Is a set threshold voltage;

step four: judging whether the software has overvoltage faults or not in the running period, if so, resetting an overvoltage fault mark and executing the step nine; if not, resetting the overvoltage fault protection mark, the overvoltage fixed time delay Udelay1 and the overvoltage reverse time delay Udelay2, and simultaneously entering the step nine;

step five: judging whether the overvoltage reverse delay Udelay2 is reached, if so, setting an overvoltage fault protection mark, and executing a seventh step and an eighth step; if not, accumulating the over-pressure difference and the integral threshold, and executing a sixth step;

step six: judging whether the overvoltage fixed time delay Udela is reached_y1, if yes, thenSetting an overvoltage fault protection mark, and executing a seventh step and an eighth step; otherwise, increasing the delay and entering the ninth step;

step seven: outputting a main contactor disconnection instruction, controlling the power generation system to quit the network, and entering the ninth step;

step eight: the controller reports the overvoltage fault to the upper computer and enters the ninth step;

step nine: and (6) exiting.

FIG. 4 is a block diagram of overvoltage fault isolation logic, the software fault isolation logic being as follows:

the method comprises the following steps: under the condition of overvoltage of a power generation system, judging the current IGCT of the generator, the line current ILCT and the rectified voltage u of the permanent magnet machine_TRU28VAnd u_LiCiWhether or not IGCT is satisfied at 0 ≤_(A,B,C)≤IGCT_{2 times load}、0≤ILCT_(A,B,C)≤ILCT_{2 times load}、 u_TRU28V<ΔU₁,u_LiCi＜ΔU₂If one of the conditions is met, executing a step two; otherwise, the fault is considered to be an overvoltage fault caused by sampling abnormality, and the sampling function is realized by the controller, so that the fault is isolated to the controller, the 'controller fault' is reported to the upper computer, and the step five is carried out;

step two: the sampling function is normal, and whether the exciting current If meets If is judged<If₀/2(If₀No-load excitation current), if yes, determining that the excitation negative line is short-circuited to the ground at the moment, isolating the fault to the excitation negative line, reporting 'overvoltage fault caused by short circuit of the excitation negative line' to the upper computer, and entering a fifth step; otherwise, entering the third step;

step three: judging whether the exciting current If meets If>2If_{2 times load}(If_{2 times load}Excitation current of 2 times of load), if so, considering that the excitation control power tube is not controlled at the moment, isolating the fault to the controller, reporting 'controller fault' to the upper computer, and entering the step five; otherwise, entering the step four;

step four: line current ILCT when judging current fault_(Current)And line current ILCT in the absence of a fault_{(without failure)}Whether or not | ILCT is satisfied_(Current)-ILCT_{(without failure)}|>Delta I, wherein the delta I is a set line current threshold value, if the delta I is met, the fault is regarded as a fault caused by sudden abnormality of an external load end, the fault is isolated to the external load, and an 'external load causes overvoltage fault' is reported to an upper computer; otherwise, the voltage regulating circuit is considered to be abnormal at the moment, the fault is isolated to the controller, and the 'controller fault' is reported to the upper computer; entering the step five at the same time;

step five: and (6) exiting.

Combining the overvoltage fault treatment with overvoltage fault isolation, the following steps can be obtained:

step three: judging generator current IGCT, line current ILCT and permanent magnet machine rectification voltage u_TRU28VAnd u_LiCiWhether or not IGCT is satisfied at 0. ltoreq._(A,B,C)≤IGCT_{2 times load}、0≤ILCT_(A,B,C)≤ILCT_{2 times load}、u_TRU28V<ΔU₁,u_LiCi＜ΔU₂If one of the conditions is met, the overvoltage fault is considered to occur at the moment, and a fifth step is executed; if the fault conditions are not met, the fault condition is regarded as an overvoltage fault false alarm caused by sampling of the controller, the controller fault is reported to the upper computer, and the step eight is carried out; wherein the IGCT_{2 times load}At 2 times the generator current, ILCT_{2 times load}At 2 times the line current, Δ U₁And Δ U₂Is a set threshold voltage;

step five: judging whether the exciting current If meets If<1/2If₀(If₀No-load exciting current), If yes, considering that the exciting negative line has short circuit to the ground, isolating the fault to the exciting negative line, reporting to the upper computer that the exciting negative line short circuit causes overvoltage fault, If not, further judging whether the exciting current If meets If>2If_{2 times load}(If_{2 times load}Excitation current of 2 times load), if so, considering that the excitation control power tube is not controlled at the moment, isolating the fault to the controller, reporting 'controller fault' to the upper computer, and if not, further judging the line current ILCT at the current fault_(Current)And line current ILCT in the absence of a fault_{(without failure)}Whether or not | ILCT is satisfied_(Current)-ILCT_{(without failure)}|>If the fault is isolated to the external load, the fault is reported to the upper computer that the external load causes overvoltage fault, otherwise, the voltage regulating circuit is considered to be abnormal in work, the fault is isolated to the controller, and the controller fault is reported to the upper computer;

step eight: and (6) exiting.

The method for diagnosing and isolating the overvoltage fault of the aircraft power generation system has the characteristics of strong anti-interference capability, intelligentized fault diagnosis strategy and the like, and effectively improves the task reliability, safety and robustness of the aircraft power supply system.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made in the above embodiments by those of ordinary skill in the art without departing from the principle and spirit of the present invention.

Claims

1. An aircraft power generation system overvoltage fault diagnosis and isolation method is characterized in that: the method comprises the following steps:

the method comprises the following steps: acquiring three-phase voltage values of the aero-generator to obtain a POR three-phase voltage maximum value POR _ MAX;

step three: judging generator current IGCT, line current ILCT and permanent magnet machine rectification voltage u_TRU28VAnd u_LiCiWhether or not IGCT is satisfied at 0 ≤_(A,B,C)≤IGCT_{2 times load}、0≤ILCT_(A,B,C)≤ILCT_{2 times load}、u_TRU28V<ΔU₁,u_LiCi＜ΔU₂If one of the conditions is met, the overvoltage fault is considered to occur at the moment, and a fifth step is executed; if the fault conditions are not met, the fault condition is regarded as an overvoltage fault false alarm caused by sampling of the controller, the controller fault is reported to the upper computer, and the step eight is carried out; wherein the IGCT_{2 times load}At 2 times the generator current, ILCT_{2 times load}At 2 times the line current, Δ U₁And Δ U₂Is a set threshold voltage;

step five: judging whether the exciting current If meets If<1/2If₀，If₀The current is no-load exciting current, if yes, the exciting negative line is considered to have short circuit to the ground, the fault is isolated to the exciting negative line, and the 'exciting negative line short circuit causes overvoltage fault' is reported to the upper computer, if not, the overvoltage fault is sent to the upper computerJudging whether the exciting current If meets If in one step>2If_{2 times load}，If_{2 times load}Is 2 times of excitation current, if the excitation current is satisfied, the excitation control power tube is considered to be uncontrolled at the moment, the fault is isolated to the controller, the controller fault is reported to the upper computer, and if the excitation current is not satisfied, the line current ILCT at the current fault is further judged_(Current)And line current ILCT in the absence of a fault_{(without failure)}Whether or not | ILCT is satisfied_(Current)-ILCT_{(without failure)}|>If the fault is isolated to the external load, the fault is reported to the upper computer that the external load causes overvoltage fault, otherwise, the voltage regulating circuit is considered to be abnormal in work, the fault is isolated to the controller, and the controller fault is reported to the upper computer;

in addition, whether the overvoltage reverse delay Udelay2 is reached is judged in the step, if yes, an overvoltage fault protection mark is set, and a seventh step is executed; otherwise, accumulating the over-pressure difference and the integral value, and executing a step six;

step eight: and exiting and waiting for entering the next period.