CN103383433B - The status monitoring of stator core of ship generator and fault early warning method - Google Patents

Abstract

The invention discloses a kind of status monitoring and temperature pre-warning method of stator core of ship generator, the method comprises: the transient state temperature rise mathematical model 1) setting up stator core of ship generator temperature rise and electric generator structure, operational factor; 2) when marine generator operating mode changes, data during collection generator operation, as sample data, use least square method to carry out parameter identification to built stator core transient state Temperature Rise Model; 3) by dynamically judging and the static method synthetic determination Generator Status judged, the early warning to generator failure is realized.In the inventive method transient state temperature rise mathematical model parameter reflection be the state of the art of generator, by real-time identification temperature model unshakable in one's determination, obtain system parameter variations situation, and judge with specified temperature rise difference synthesis, accurately can judge Generator Status, realize generator stator core fault pre-alarming.<!--1-->

Description

The status monitoring of stator core of ship generator and fault early warning method

Technical field

The present invention relates to the monitoring of Generator Status, refer to a kind of status monitoring and fault early warning method of stator core of ship generator particularly.

Background technology

Generator is a kind of energy converting between mechanical mechanism, in conversion process of energy, inevitably produce loss, and the final overwhelming majority of these losses becomes heat, and heat eliminating medium will wherein a part be taken away, and remaining will make motor each several part temperature raise.Generator loss divides by the position produced can be divided into core loss, winding loss and mechanical loss three major types.Stator core loss and winding loss occupy quite large proportion in the whole loss of electric machine.Motor running overload, asymmetric operation, cooling system failure, fault unshakable in one's determination, insulation fault etc. all can cause electric machine stator iron overheated, and its temperature rise is increased.Stator core temperature is too high, will accelerate the aging of unshakable in one's determination and stator coil, affect motor serviceable life and operational reliability.Therefore significant to the on-line monitoring of stator core temperature rise.

The heat monitoring of current stator core of ship generator mainly leans on the temperature sensor be equipped with in generator to realize.For air cooled generator, at stator core interlude and limit section all embedding some resistance-type thermometry meters or thermo-couple thermometry meter.Fault alarm method realizes with threshold mode, and when namely temperature exceedes a certain alarming value, supervisory system provides alerting signal.It is pointed out that the temperature that just cooling system and insulating material that threshold value reflects can bear, is not the direct criterion formulated for generator state monitoring and fault pre-alarming object.

The specified temperature rise of generator, can as the important indicator characterizing Generator Status.And the temperature rise that current control and monitoring system for ships measures, just reflect the real-time temperature rise of generator under different work condition state, the index characterizing Generator Status can not be used as.The temperature rise of generator is the result of the every loss of motor and cooling system heat exchange action, and the thermal source loss of the height of temperature rise, the speed of temperature rise speed and each operating point and thermal resistance, thermal capacitance are relevant.Thermal source loss is made up of eddy current loss, stray loss, winding loss, wind moussing loss etc., and the size of thermal resistance is relevant to factors such as the wind speed of respective point, insulation thickness, isolation material, area of dissipations.Current supervisory system can not obtain electric machine structure parameter according to real-time temperature rise, thus also just cannot judge that whether generator system state is normal.There is few stock circle line turn-to-turn short circuit or the blocking of indivedual air channels in such as stator winding, the motor local overheating caused.Marine generator, for guaranteeing security of operation, can reserve sufficient allowance, and therefore generator can not be operated in declared working condition.To a certain degree rise although the temperature of therefore monitoring has, can't reach alarm threshold value, motor still can normally work.The now temperature rise that records of supervisory system is not the specified temperature rise of generator, can not be used as the index characterizing generator system state.Monitor staff cannot make according to motor operating parameter and monitoring point temperature conditions the anticipation that generator is in bad running status.Therefore there is certain defect in existing fault alarm.

For improving marine generator status monitoring and fault pre-alarming design, current main flow thinking is: set up generator stator core temperature rise and the unified model between electric generator structure and operational factor first theoretically, then based on a large amount of real data time normally to run under different steady working condition, by least square method, identification is carried out to model, the standard value of the stator core temperature model calculating generator stator core temperature under different running status obtained by identification.During generator operation, the standard value calculated under the temperature recorded by supervisory system and current working is made comparisons.If higher than set threshold value, then temperature monitoring system is reported to the police.Based on above-mentioned thinking, only need to carry out identification to Temperature Rise Model in advance, then by calculating standard value to the model of identification.According to this kind of thinking, stator core temperature rise identification only need be studied stator steady-state model, and identification work is only carried out before generator installation and operation.

But above-mentioned thinking has 3 weak points, and one is: the threshold value set by temperature rise is setting arbitrarily, and the threshold value at different generator, different motor position is not identical, the setting not science of threshold value.Two are: the temperature rise of stator core is relevant to the numerous structural parameters of generator, and the fluctuation of the different parameters temperature rise impact on iron core can be cancelled out each other, and the temperature recorded by sensor merely and the standard value of calculating are made comparisons, can only preliminary judgement Generator Status.Three are: above-mentioned thinking, only determine the standard temperature rise of generator under this operating mode, according to the difference of standard temperature rise and actual temperature rise, judge Generator Status.Do not consider generator structural parameters situation of change in this condition.

Summary of the invention

The present invention, on above-mentioned prior art basis, provides a kind of status monitoring and temperature pre-warning method of stator core of ship generator.The method is by every electrical parameters when monitoring, the operating mode conversion of collection generator and thermal parameter changing value, use system identifying method, parameter identification is carried out to generator stator core transient state Temperature Rise Model, data analysis determination credibility scope is carried out, as system alarm decision condition by each model parameter obtained identification.Meanwhile, to the specified temperature rise of identification model calculating generator, consider parameter index and specified temperature rise index, generator unit stator heart shaped state is assessed and fault pre-alarming accurately.

The technical scheme realizing the inventive method employing is: a kind of status monitoring of stator core of ship generator and temperature pre-warning method, comprising:

1) the transient state temperature rise mathematical model of stator core of ship generator temperature rise and electric generator structure, operational factor is set up;

2) when marine generator operating mode changes, data during collection generator operation, as sample data, use least square method to carry out parameter identification to built stator core transient state Temperature Rise Model;

3) by dynamically judging and the static method synthetic determination Generator Status judged, the early warning to generator stator core fault is realized;

Described dynamic judgment method comprises:

The parameter obtained identification is carried out adaptive threshold and is determined, at the normal initial operating stage of marine generator system, continuously identification is carried out to system, calculate the predicted value of nominal parameter, statistical study is carried out to the predicted value of gained nominal parameter, with early stage experiment value as a reference, calculate the credibility scope of described forecast ratings normal distribution, using the probability distribution of confidence values as warning decision condition;

Described static decision method comprises:

To the transient state Temperature Rise Model unshakable in one's determination that marine generator System Discrimination obtains, give rated condition input, obtain the specified temperature rise calculated value Δ t of stator core _fe1, by Δ t _fe1the specified temperature rise value Δ t of stator core when value and generator system normally run _fe0relatively, judge whether generator stator core breaks down.

In technique scheme, sample data when gathering generator operation comprises: generator voltage, active power, reactive power, each point for measuring temperature temperature unshakable in one's determination and each point for measuring temperature temperature of stator winding, coolant temperature around unshakable in one's determination; Wherein, generator voltage, active power, reactive power, coolant temperature are as input data; Stator core temperature, stator winding temperature is as output data.Pre-service is carried out, to improve Precision of Parameters Identification to the data gathered.Data prediction comprises the rejecting, data smoothing, filter away high frequency noise etc. of outlier.System Discrimination means (least square method) is used to carry out parameter identification to built stator core transient state Temperature Rise Model;

The inventive method has the following advantages:

1, the present invention is judged and dynamic judgment method by static, can accurately judge marine generator state, realize marine generator fault pre-alarming.

2, by the parameter that identification stator core transient state Temperature Rise Model obtains, Generator Status details can correctly be reflected.This parameters in series is not unalterable, but correspondingly changes along with Generator Status quality.This parameters in series is the comprehensive parameters had after the mutual computing of parameter of physical significance by a group, can reflect the state of generator equally.Therefore only need this comprehensive parameters of identification, there is no need to continue design parameter, carry out Mathematical.

Accompanying drawing explanation

Fig. 1 is a kind of synchronous AC motor stator structure schematic diagram of radial ventilation;

The two thermal source thermal circuits of Fig. 2 for dispelling the heat between the stator core of synchronous AC motor shown in Fig. 1 and stator winding.

Fig. 3 is the process flow diagram of generator state monitoring of the present invention and fault early warning method.

Embodiment

Below in conjunction with the drawings and specific embodiments, the present invention is described in further detail.

Shown in Fig. 1 is the embodiment of the medium-sized alternating-current motor stator schematic diagram of a radial ventilation, and its thermal circuits is shown in Fig. 2.Motor is a kind of energy converting between mechanical mechanism, in energy converting between mechanical process, unavoidably will produce loss, and the final overwhelming majority of these losses becomes heat, and motor each several part temperature is raised.Electric machine stator iron temperature raises and determines primarily of stator core loss and stator winding loss.Note P _cufor generator unit stator winding loss, P _fefor generator stator core loss.R _c1for heat is from the surperficial thermal resistance passing to air of winding overhang; R _c2for the thermal resistance of air is passed on heat winding surface from ventiduct; R _cFfor the thermal resistance between winding copper and iron; R _f1for the thermal resistance that the heat of iron core generation sheds from ventiduct surface; R _f2for the thermal resistance that heat sheds from iron core inner circle surface; R _f3for the thermal resistance that heat sheds from outer round surface unshakable in one's determination.

As shown in Figure 3, generator state monitoring and fault early warning method comprise following concrete steps:

S100: for specific ship generator mark, sets up the transient state temperature rise mathematical model of generator stator core temperature rise and electric generator structure, operational factor.Different generator is due to radiating mode difference, and transient state temperature rise mathematical model is also different;

Stator winding loss and stator core loss are the principal elements causing stator core temperature rise to increase.Generator unit stator winding loss

$P_{\mathrm{Cu}}=3I^2{R}_t=3\frac{P^2+Q^2}{U^2}{R}_t---(1-1)$

R _tfor stator winding resistance value at the corresponding temperature, this resistance is relevant to temperature linearity.

Generator stator core loss can simply be divided into main field and stray field to change the loss caused in iron core, and loss main field caused is designated as P _fe1, the loss that stray field causes is designated as P _fe2.Loss total in iron core is the loss sum that main flux and leakage flux produce respectively, and note stator core loss is P _fe.

K _fefor constant coefficient, G _fefor stator core weight, k _a, k _f, k _zfor the scale-up factor of magnetic flux density and electromotive force, X _σ, X _a, X _dfor Stator, the reactance of armature reaction, synchronous reactance, for power-factor angle.The concrete derivation list of references " determination based on the turbine generator stator core standard temperature of status monitoring " of formula.

If stator core and winding are all isothermal heaters, according to the interactional degree of temperature in both heating processes, they are considered as the isothermal heater affected each other, its balance equation of heat energy is:

$\left\{\begin{array}{c}{c}_{\mathrm{cu}}{m}_{\mathrm{Fe}}\frac{d{\mathrm{\&theta;}}_{\mathrm{cu}}}{\mathrm{dt}}+\frac{{\mathrm{\&theta;}}_{\mathrm{cu}}}{R_{\mathrm{cu}}}+\frac{{\mathrm{\&theta;}}_{\mathrm{cu}}-{\mathrm{\&theta;}}_{\mathrm{Fe}}}{R_{\mathrm{CF}}}=P_{\mathrm{cu}}\\ c_{\mathrm{cu}}{m}_{\mathrm{Fe}}\frac{d{\mathrm{\&theta;}}_{\mathrm{Fe}}}{\mathrm{dt}}+\frac{{\mathrm{\&theta;}}_{\mathrm{Fe}}}{R_{\mathrm{Fe}}}+\frac{{\mathrm{\&theta;}}_{\mathrm{Fe}}-{\mathrm{\&theta;}}_{\mathrm{cu}}}{R_{\mathrm{CF}}}=P_{\mathrm{Fe}}\end{array}\right.---(1-3)$

Solution balance equation obtains:

$\left\{\begin{array}{c}{\mathrm{\&theta;}}_{\mathrm{cu}}=C_{\mathrm{cu}1}{e}^{(-A+D)t}-C_{\mathrm{cu}2}{e}^{(-A-D)t}+\frac{P_{\mathrm{Fe}}+\frac{R_{\mathrm{cu}}}{R_{\mathrm{CF}}+R_{\mathrm{cu}}}{P}_{\mathrm{cu}}}{\frac{1}{R_{\mathrm{cu}}}+\frac{1}{R_{\mathrm{Fe}}}-\frac{R_{\mathrm{cu}}}{R_{\mathrm{CF}}^2+R_{\mathrm{CF}}{R}_{\mathrm{cu}}}}\\ {\mathrm{\&theta;}}_{\mathrm{Fe}}=C_{\mathrm{Fe}1}{e}^{(-A+D)t}-C_{\mathrm{Fe}2}{e}^{(-A-D)t}+\frac{P_{\mathrm{cu}}+\frac{P_{\mathrm{Fe}}}{R_{\mathrm{CF}}+R_{\mathrm{Fe}}}{P}_{\mathrm{Fe}}}{\frac{1}{R_{\mathrm{cu}}}+\frac{1}{R_{\mathrm{Fe}}}-\frac{R_{\mathrm{Fe}}}{R_{\mathrm{CF}}^2+R_{\mathrm{CF}}{R}_{\mathrm{Fe}}}}\end{array}\right.---(1-4)$

Wherein,

$A=\frac{c_{\mathrm{cu}}{m}_{\mathrm{cu}}(\frac{1}{R_{\mathrm{CF}}}+\frac{1}{R_{\mathrm{Fe}}})+c_{\mathrm{Fe}}{m}_{\mathrm{Fe}}(\frac{1}{R_{\mathrm{CF}}}+\frac{1}{R_{\mathrm{cu}}})}{2c_{\mathrm{cu}}{c}_{\mathrm{Fe}}{m}_{\mathrm{cu}}{m}_{\mathrm{Fe}}}$ ；

$B=\frac{(\frac{1}{R_{\mathrm{CF}}}+\frac{1}{R_{\mathrm{cu}}})(\frac{1}{R_{\mathrm{CF}}}+\frac{1}{R_{\mathrm{Fe}}})-\frac{1}{{R_{\mathrm{CF}}}^2}}{2c_{\mathrm{cu}}{c}_{\mathrm{Fe}}{m}_{\mathrm{cu}}{m}_{\mathrm{Fe}}}$ ；

$D=\sqrt{A^2-B}$ ；

Simultaneous (1-1), (1-2), (1-4) obtain:

$\left\{\begin{array}{c}{\mathrm{\&theta;}}_{\mathrm{cu}}=C_{\mathrm{cu}1}{e}^{-\frac{t}{T_1}}-c_{\mathrm{cu}2}{e}^{-\frac{t}{T_2}}+a_1{I}^2+b_{1}Q+c_2{U}^2\\ {\mathrm{\&theta;}}_{\mathrm{Fe}}=C_{\mathrm{Fe}1}{e}^{-\frac{t}{T_1}}-C_{\mathrm{Fe}2}{e}^{-\frac{t}{T_2}}+a{I}^2+\mathrm{bQ}+c{U}^2\end{array}\right.---(1-5)$

Can find out that stator temperature rise system is the linear system that one three input two exports by formula (1-5).Writ state variable x ₁=θ _cu, x ₂=θ _fe, then state equation is

$\begin{array}{c}\left[\begin{array}{c}\stackrel{.}{{\mathrm{\&theta;}}_{\mathrm{cu}}}\\ \stackrel{.}{{\mathrm{\&theta;}}_{\mathrm{Fe}}}\end{array}\right]=A\left[\begin{array}{c}{\mathrm{\&theta;}}_{\mathrm{cu}}\\ {\mathrm{\&theta;}}_{\mathrm{Fe}}\end{array}\right]+B\left[\begin{array}{c}{I}^2\\ Q\\ U^2\end{array}\right]\\ Y=C\left[\begin{array}{c}{\mathrm{\&theta;}}_{\mathrm{cu}}\\ {\mathrm{\&theta;}}_{\mathrm{Fe}}\end{array}\right]+D\end{array}---(1-6)$

In formula, $A=\left[\begin{array}{cc}-(\frac{1}{c_{\mathrm{cu}}{m}_{\mathrm{cu}}{R}_{\mathrm{cu}}}+\frac{1}{c_{\mathrm{cu}}{m}_{\mathrm{cu}}{R}_{\mathrm{CF}}})& \frac{1}{c_{\mathrm{cu}}{m}_{\mathrm{cu}}{R}_{\mathrm{CF}}}\\ \frac{1}{c_{\mathrm{Fe}}{m}_{\mathrm{Fe}}{R}_{\mathrm{CR}}}& -(\frac{1}{c_{\mathrm{Fe}}{m}_{\mathrm{Fe}}{R}_{\mathrm{Fe}}}+\frac{1}{c_{\mathrm{Fe}}{m}_{\mathrm{Fe}}{R}_{\mathrm{CF}}})\end{array}\right]$ ;

$B=\left[\begin{array}{ccc}\frac{3R_t}{c_{\mathrm{cu}}{m}_{\mathrm{cu}}}& 0& 0\\ \frac{m_1}{c_{\mathrm{Fe}}{m}_{\mathrm{Fe}}}& \frac{m_2}{c_{\mathrm{Fe}}{m}_{\mathrm{Fe}}}& \frac{m_e}{c_{\mathrm{Fe}}{m}_{\mathrm{Fe}}}\end{array}\right]$ ；

$C=\left[\begin{array}{cc}1& 0\\ 0& 1\end{array}\right]$ ；D=0；

Formula (1-6) is rewritten as transfer function matrix is;

$G\left(s\right)=C{(\mathrm{sI}-A)}^{-1}B=\frac{1}{s^2+\mathrm{as}+b}\left[\begin{array}{ccc}{g}_{11}s+f_{11}& g_{12}s+f_{12}& g_{13}s+f_{13}\\ g_{21}s+f_{21}& g_{22}s+f_{22}& g_{23}s+f_{23}\end{array}\right]---(1-7)$

Stator core temperature rise θ can be found out by formula (1-5) _fewith reactance of armature reaction X _a, synchronous reactance X _d, leakage reactance X _σ, winding resistance value R _t, scale-up factor k _a, k _z, k _f, constant coefficient K _fethe coefficients such as appropriate section thermal resistance resistance are relevant.From formula (1-7), to the data of data acquisition system, carry out identification, formula (1-7) transfer function model can be obtained, this group model parameter (a, b, g ₁₁, g ₁₂, g ₁₃, g ₂₁, g ₂₂, g ₂₃, f ₁₁, f ₁₂, f ₁₃, f ₂₁, f ₂₂, f ₂₃) there is no concrete physical significance, but the appearance of a lot of fault is often associated with the numerical value change of some physical parameters, and there is certain implication relation in model parameter and physical parameter.This group model parameter can correctly reflect generator system state.When generator normally runs, this group parameter fluctuates within the specific limits.

Step S200: the data gathering the conversion of generator operating mode, the data gathered comprise: generator voltage, active power, reactive power, each point for measuring temperature temperature unshakable in one's determination and each point for measuring temperature temperature of stator winding, coolant temperature around unshakable in one's determination, and pre-service is carried out to the data gathered, pre-service adopts the method such as data filtering, unruly-value rejecting.Then least square method is used to carry out parameter identification to built stator core transient state Temperature Rise Model.

Record cast parameter a, b, g ₂₁, g ₂₂, g ₂₃, f ₂₁, f ₂₂, f ₂₃, this model parameter is transient state temperature rise load transfer function coefficient unshakable in one's determination.The one group of parameter obtained the continuous identification of marine generator system is carried out adaptive threshold and is determined.At the normal initial operating stage of marine generator system, continuously identification is carried out to marine generator system, thus calculate the predicted value of nominal parameter.Statistical study is carried out to a large amount of forecast ratings, with early stage experiment value as a reference, calculate the credibility scope of its normal distribution.Using the probability distribution of confidence values as warning decision condition.

Step S300: the stator core Temperature Rise Model obtained identification, gives rated condition input, calculates the specified temperature rise Δ t of stator core _fe1(the temperature rise index of current system), calculates Δ t _fe1with Δ t _fe0(the temperature rise index under generator unfaulty conditions) difference.

Consider nominal parameter fluctuation and temperature rise index difference two aspect factors, synthetic determination Generator Status.If parameter and specified temperature rise have one to reach alert if, can report to the police.

As previously mentioned, according to embodiments of the invention, do not need the standard value of each operating mode of calculating generator, the parameter that identification obtains and temperature rise index accurately can reflect system now state of the art.By Parameters variation and temperature rise difference comparsion, Generator Status can be judged fast, reach generator state monitoring and fault pre-alarming object.By changing mathematical model, method provided by the invention, also can be applicable in rotor windings temperature, bearing temperature early warning.

Be more than that detailed reference is provided to enforcement of the present invention, although the present invention is undertaken setting forth and illustrating by these embodiments, should be noted that the present invention is not merely confined to these embodiments.On the contrary, all substitutes, variant and the equivalent in invention spirit and invention scope that appended claim defines is contained in the present invention.

Claims (2)

1. the status monitoring of stator core of ship generator and a temperature pre-warning method, is characterized in that, comprising:

1) the transient state temperature rise mathematical model of stator core of ship generator temperature rise and electric generator structure, operational factor is set up;

2) when marine generator operating mode changes, data during collection generator operation, as sample data, use least square method to carry out parameter identification to built stator core transient state Temperature Rise Model;

3) by dynamically judging and the static method synthetic determination Generator Status judged, the early warning to generator stator core fault is realized;

Described dynamic judgment method comprises:

The parameter obtained identification is carried out adaptive threshold and is determined, at the normal initial operating stage of marine generator system, continuously identification is carried out to system, calculate the predicted value of nominal parameter, statistical study is carried out to the predicted value of gained nominal parameter, with early stage experiment value as a reference, calculate the credibility scope of the predicted value normal distribution of described nominal parameter, using the probability distribution of confidence values as warning decision condition;

Described static decision method comprises:

To the transient state Temperature Rise Model unshakable in one's determination that marine generator System Discrimination obtains, give rated condition input, obtain the specified temperature rise calculated value Δ t of stator core _fe1, by Δ t _fe1the specified temperature rise value Δ t of stator core when value and generator system normally run _fe0relatively, judge whether generator stator core breaks down.

2. the status monitoring of stator core of ship generator and temperature pre-warning method according to claim 1, it is characterized in that, described sample data comprises: generator voltage, active power, reactive power, each point for measuring temperature temperature unshakable in one's determination and each point for measuring temperature temperature of stator winding, coolant temperature around unshakable in one's determination; Wherein, generator voltage, active power, reactive power, coolant temperature are as input data; Stator core temperature, stator winding temperature is as output data.