TW201043532A - Short-circuit current detection method for ship - Google Patents

Abstract

A short-circuit current detection method for a ship includes the following steps: firstly, presetting and calculating a required field space, secondly determining whether or not the quantity of the power generator to be checked is less than one, if yes, an error message is displayed, if no, clearing the previous calculated input and result content. Next, an input data group is inputted, and a set of impendence values is established to calculate the current of the generator and the motor. Afterward, the synthesis parameters of the bus are calculated, and the synthesis current of the bus is calculated sequentially. Finally, an output result group is outputted. Accordingly, by inputting the relative parameters of the power system and calculating current of the generator and the motor, and the synthesis parameters and synthesis current of the bus, a more precise short circuit current is obtained to achieve the purpose of reducing the damage risk of equipments due to short circuit.

Description

201043532 VI. Description of the Invention: [Technical Field] The present invention relates to a current detecting method, and more particularly to a ship short-circuit current detecting method. [Prior Art] In the actual operation of the ship's power system, short-circuit faults are difficult to avoid, and natural aging, mechanical damage, and improper operation of the insulation may cause a short circuit. When a short circuit occurs near the main busbar in the ship's power system, a short-circuit current that is much larger than the normal value will occur. In addition, when the short-circuit fault occurs, the total impedance of the system is small, and the most severe short-circuit condition is often caused by a metal. Sexual short circuit. Furthermore, the 'system short-circuit impedance is also extremely correlated with the position of the short-circuit point. The closer the short-circuit point is to the power supply, the smaller the total system impedance is. Relatively, the short-circuit. The current value is larger, even if the short-circuit occurs for a short time. The mechanical stress and thermal effects of strong short-circuit currents can cause serious damage to the generator or other related devices. In addition, the short-circuit current will also cause the grid voltage to drop, which will affect the operation of the equipment, so that the running of the motor will stop the performance of the special performance. Therefore, it is said that the short-circuit current has the following conditions for the damage caused by electrical equipment: (1) It causes heat and loss of electrical equipment. (2) Cause a large voltage drop, and the motor speed drops, or even stops running. (III) Generating large mechanical stresses Bowing and deformation of current-carrying parts of electrical equipment 3 201043532 (4) When the air is short-circuited early, the unbalanced current and magnetic field are generated, which affects the control of communication and related equipment. <(5) If a short-circuit current occurs near the power supply, it will cause the generator or other equipment to lose synchronization and disassociation and affect the operation of the system. It can be seen from the above that the short-circuit current has a great (four) 'current (four) electrical phase problem. The fourth (four) protection device can quickly cut off the line of the faulty device to prevent the fault current from continuing to flow and minimize the damage range. . A commonly used protection device in a ship's power system, such as a fuse or circuit breaker 'CB. In addition, an arc is generated when the fault current is turned off. Therefore, the aforementioned protection device must also have an arc-extinguishing force to safely turn off the fault current. Furthermore, in addition to using the method of breaking the fault current to deal with the short-circuit current problem, the relevant power distribution equipment, such as H wire, bus bar, sectional switch, transformer, etc., must be able to withstand the thermal effects and mechanical stress generated by the instantaneous fault current. That is, there must be a large equipment short-circuit strength. Therefore, when designing the ship's power supply system, the fault currents in the system must be calculated before the appropriate protection equipment can be selected to ensure the safety and reliability of the power supply. Today, the general calculation of the short-circuit current of ships is based on the old international standard IEC 60363, and the short-circuit capacity of circuit_breakers in ships is the main content. The impedance of the electrical equipment is converted. 201043532 'Simplify the fault impedance and other calibration impedance and calculate the short-circuit fault current. However, in the current practical application, it is still found that the short-circuit current calculation reference of the ship has the following disadvantages: (-) Ignore the generator before the fault Load effect: (1) Ignore the transient decay of the AC component. (3) Ignore the motor energy conversion efficiency. (4) Ignore the short-circuit current fed by the shaft power generation system. (5) Ignore the influence of the cable operating temperature. The production, official, and academic circles are eager to develop a method for calculating the magnitude of fault currents generated by short-circuit accidents at different locations in the ship's power system, so that when the ship's power allocation plan is planned, it is better to pre-select enough. Broken capacity protection device, and fast The ground equipment or line is cut off from the power supply, and the range of power failure area caused by the short circuit and the related electrical appliance damage caused by the short circuit are minimized. [Invention content] When calculating the short circuit current, it is understood by the individual equipment The short-circuit current ° condition and the influence of multiple power devices in the system on the short-circuit current is very important. In a complete ship power system, the passive components in the system, such as electron mirrors and transformers, are very short to the short-circuit current (four). A, in addition to changing the steady-state value of the calculation result of the open circuit current, the characteristic data representing the transient process is also affected. Therefore, the object of the present invention is to provide a ship short-circuit current detecting method to obtain accurate short-circuit current. The calculation result is as follows. The ship short-circuit current detecting method of the present invention comprises the following steps 201043532 (a) inputting an input data group. (b) establishing a set of impedance values. (c) calculating the generator and motor currents. (d) calculating Bus combines the parameters. (e) Calculates the bus combiner current. (f) Outputs an output result group. The ship short-circuit current detection method is used to calculate the generator and motor electric junction, the bus-synthesis parameter and the bus-synthesis current for the wrinkle input data group and the established impedance value, and then obtain the short-circuit current of 2 ships to reduce The failure of the related electrical equipment due to a short circuit, or even the risk of damage. [Embodiment] The foregoing and other technical contents, features and effects of the present invention are described in detail below with reference to a preferred embodiment of the drawings. Referring to FIG. 1 , a preferred embodiment of the ship short-circuit current detecting method of the present invention includes the following steps: ^ Firstly, as shown in step 11, the at least one required for the money measurement is pre-set. It facilitates the convenience of subsequent test results interpretation and facilitates debugging if an error occurs in the calculation. , as shown in step 12, the user determines whether the number of generators to be detected is less than 1: If yes, an error message is displayed as shown in step 121, and the detection is terminated by step 201043532. If not, then as shown in step 122, the previously calculated input and result contents are cleared and the next step is performed. Then, as shown in step 13, an input data group is input. In the preferred embodiment, the input data group is provided by a human machine interface developed by Microsoft (Micr〇s〇ft) Excel software, and the home page interface is shown in FIG. 2, and the input is performed. The data group further includes: a set of equipment basic data, a set of transformer line parameters, a set of fault point line parameters, and a set of line basic parameters. Therefore, the human-machine interface provides complex input paging relatively, including: a generator parameter input page (see Figure 3), a transformer parameter input page (see Figure 4), and a motor parameter input page (see Figure 5). A bus voltage input page (see Figure 6), a line impedance input page (see Figure 7), a transformer line parameter input page (see Figure 8), a fault point line parameter input page (see Figure 9), and a Cable impedance parameter input page (see Figure 10). According to the above, the basic data of the device is respectively composed of the generator parameter input page, the transformer parameter input page, the motor parameter input page, the bus voltage input page and the line impedance input page. The transformer line parameters are typed via the transformer line parameter input tab. The fault point line parameter is provided via the fault point line parameter input tab. The basic parameters of the line are entered by the cable impedance parameter input tab. Here, the content of each data in the input data group is further explained: 7 201043532 (1) The basic information of the equipment includes: a generator apparent power (Sg, unit is kVA), one Generator rated voltage (Vg, unit is v), one generator secondary transient reactance (X"d, unit is %), one generator transient reactance (x, d, unit is %), one generator reactance ( Xd unit is %), one generator secondary transient time constant (T"d, unit is sec), one generator transient time constant (T, d, unit is see), one generator DC time constant (Tdc, The unit is this magic, _ generator stator resistance (Rs 'unit is %), a generator frequency (f, the unit is Hz), a generator rated current ratio (KKd 'unit is %), a generator power factor ( PF), a transformer apparent power (str, the unit is kVA), a transformer once measured voltage (Vpri, the unit is V), a transformer secondary measured voltage (Vsec, the unit is V), a transformer internal resistance (Rtr, Unit is %), a transformer internal reactance (Xtr, in %), The motor operating state value, a total power of the motor (in kw), a motor apparent power (Sim, in units of kVA), a

Motor rated current (Iim, single A) 'A motor short-circuit current AC component (Iacim, unit a), a motor short-circuit current value component (Idcim, unit A), a motor short-circuit current peak (Ipeakim, the unit is a sentence , a bus voltage group (including MSB Pri, MSB Sec, eSB Pd, ESB Sec Z fwd, the unit is v), and a line impedance value group (including Rc and, the unit is the resistance value / m). The parameters of the transformer line include: the diameter of a transformer once measured (unit is mm2), the diameter of a transformer secondary measurement line (unit is mm2), the number of parallel connections of a transformer, and the length of a transformer line (unit is (7)). ―) The fault line parameters of the group include a fault point line diameter (unit: ηπη2), a fault point line parallel quantity, and a fault point line length (single 201043532 bits are m). (4) The basic parameters of the line are included The line resistance parameter (Rc, the unit is electric difficulty / m) and a line reactance value (xc, the unit is the reactance value of the main water use in practice, the ship short-circuit current detection method of the present invention, in addition to mainly used to detect power generation „ „ Ai! The fault current status of the Ai! can also be used to detect the fault group of the motor (8). For this reason, the input data group mentioned above may also include the following benefits _ 丄 see ln not - Motor basic parameter input paging (see

G ❹ Group motor parameters. One motor rated voltage (in 乂), one motor frequency (unit 蛊 only, horse W hand (early position Hz), - motor power factor, sub-resistance (unit is %), one $ up Greedy Emperor Runs Thunder m... (Unit is %), - Motor turns snow m"., Receiver reactance (soap level is %), - Motor is always ten - Motor line diameter (unit is mm2), - Motor line Length (in m), _ $ 蝻攸 碰 ^ ^ Motor circuit parallel number, one motor line resistance is ohm), and - motor line reactance (in ohms). In addition, to calculate more accurately When the fault current of the motor is out, the motor parameters listed above can be added _ motor change (four) resistance (unit is %), one: transformer reactance (unit is %), one motor transformer once rated voltage (early position V) 'and- motor transformer secondary rated voltage (in V) and other departments for more precise calculations. However, this detection function is flexible and selective, therefore, the method provided by the present invention, Can be applied to match with emergency generators, emergency horses , other conventional technical fields or future related electrical equipment inspection, so the class situation is not the focus of the present invention, so here is no longer a brief description of the 〇9 201043532 effort step 14 does not establish the group impedance value. In the good example, the establishment of the impedance value of the group is calculated according to the following method: firstly multiplying the line resistance by the line length and dividing by the number of lines connected in parallel and dividing by the value of the resistor to obtain the resistance value. Then, the circuit reactance multiplies the line. The length is divided by the number of parallel lines, and then divided by 1 〇〇〇 to obtain the reactance value. Next, as shown in step 15, the generator and motor currents are calculated. It is worth mentioning that, in the preferred embodiment, Before starting the calculation of the generator and motor current, as shown in step 151, it is first determined whether the total power of one of the motors to be calculated is greater than 1 kW: If so, as shown in step 152, the motor is determined to be large. Motor, and set &2"M = 0.16pM, =, & =0·034ρ.Μ·, Λ/?=〇〇21ρ, and % = % + A = 0.055ρ.Μ·, proceed to the next step. If no, then as in step 153 It is determined that the motor is a small motor, and δ is 疋Z"M=〇_2_P.w·, = 0.188pw, with two 0.043/>·«.' ” and=0.027/?.w, and = rs + M = 〇·〇7〇Ρ'μ·, proceed to the next step. The above two conditions are the sub-transient impedance of the non-synchronous motor, χ, Μ is the sub-transient state, Rr is the rotor motor of the non-synchronous motor, and Rs is the non-synchronous electric motor (the J stator resistance, the Rm is the motor resistance). In addition, the aforementioned generator and motor currents are calculated as follows: Z"M=\rR+Rs^R)2^R+Xs+X)2\XI2 ' ΓΜ-51^ ' IacM=^IrM idcM(t) = 42(lM si^M)e~t/T^M ' lpM=^>hu ' X, ----1 CUM milk=Γ'M e-Ά, IpM it)=core IacM (ή +1dM Price T'' ω. jr^r) 1m E:

U \2 cos φΜ

UrM

Sin φΜ - ^mK :E Z V· 'tf

U 1/2 10 201043532 Ε'μ ' and Ζ''Μ is a non-synchronized mine with ^ 萆 sub-transient impedance, R is non-rotor resistance, RS is the resistance resistance of the line between the four-step motor bus bars, R is the generator-to-mains r, x is reduced to the line between the generator and the main busbar + snow Z, T". The rotor reactance s is a sub-mesh of the non-synchronous motor, and the secondary short-circuit of the 5-step motor The symmetrical short circuit of the current effect motor feed.

Electric "a is the equivalent motor rated current, IPM is the maximum asymmetric short-circuit current, T', M is the sub-transient time constant, TdeM is the DC time constant, Xm is the non-synchronous motor reactance~, E"4 E, M is the secondary transient and transient internal potential of the short-circuit instant motor, SIN0M and COS0M are motor power factor, 2, the secondary transient impedance of the asynchronous motor, urM is the rated voltage of the motor, and IdeM is the equivalent motor feed. The non-periodic short-circuit current. Then, the bus-synthesis parameter is calculated as shown in step 16. In the preferred embodiment, the bus-synthesis parameter is calculated as follows: ^ac - ^αοΟχ + ^acG2 +- ' + ^acGn + ^acMx +1acM2 +--- + 1 acMm , IP=IpGl+IpG2+- + IpGn+IpMl+IpM2+-- + IpMm ' 1 ac _MGi = I〇〇~ I acG, , for i=l To η, /p—' for i=l to m,

JacG it)m = ΣΙα〇β (0 + Σ acM (〇, ^cG^TO = Z^cG(0 + Z^cA/(0, Z* =, x'* = ^Z?-R*, X * = -Jz*2 ~r} , Z* = +χ}, = Rcp + Rt + Rcs, = Xcp + Xt + Xcs, X* ="Z*2 - Jii ' X* = -Jz* -Ri z : z:

UpSi: .U〇 λ/37: Z:=W'Zt=^ U〇 z; -, c3 = 2Λ* X: V^'z,=VJT'C3 27tfTdct ur z; +z: ' 11 = X:

Res X Ks = X (jf)2' A = ^ X (3⁄42 ss 11 p 201043532 and u* is the equivalent of the generator, u0 is the line voltage impedance before the fault, and the G3 is equivalent The first ten different cranes, 1 * is the equivalent generator current, !' and !, * are respectively == the machine's secondary transient short-circuit current and transient short-circuit current, r* is the equivalent generator resistance, 'for The non-periodic component time constant, X* is the equivalent generator reactance H and η are the equivalent transient reactance and transient reactance of the generator, ζ* is the effective generator impedance, and l is the main bus fault point. Symmetrical short-circuit, -Wn is the AC component of the short-circuit current of the synchronous motor,

IacM1~m is the symmetrical short-circuit current of the non-synchronous motor, 1 is the main bus fault point = the maximum asymmetric short-circuit current, "η is the asynchronous motor asymmetric short-circuit current component, Wm is the non-synchronous motor asymmetric short-circuit current component, lac- MGi and IPMGi are respectively _ fault point symmetry and maximum asymmetric short-circuit current, I- is the short-circuit current non-periodic component fed by the generator, ^ fish ^ is the equivalent motor feeding symmetrical and non-periodic short-circuit current, wide ', I is the secondary transient short-circuit current and transient short-circuit current of the equivalent generator, called and us are the transformer primary measurement and the secondary measurement respectively, t is the short-circuit start period Rcp and R'cs are the first measurement and Switch to the secondary measurement line resistance of one measurement, < all power equipment resistance algebra between the main bus and the fault point and Rt is the resistor resistance, not all the power between the main bus and the fault point, and the reactance algebra and Χα^ χ, respectively, __ subtest and conversion to - subtest: secondary measurement line reactance, & for the transformer reactance, U county secondary side power and then 'as shown in step 17' to calculate the convergence Row synthesis In the present embodiment, the bus current is calculated as follows: 12 201043532 M*=/,w,*, 八七, /:=ΣΓ4ή·+Σ%, /:=ς?4 *, h* =Σ?/ωί, ["(,) = (ϋ)"Ά + , /rfcG =万/>, K (t) = M*e~t/Td* +/; ' Κ\^=Σ^Κ\ί) + ΣΤΐΜ^ίΙΓκί,

Td^H[iacG(tx),+ik.))/Nf JacG(tx)*=M,e-^/Td* +Ν^'η* +4φ , 1αΑίχ)^ =YjacGitx)t +^Ιααί( χ χ, H) * = Σ; 'mail ('χλ+Σ:, secret (recognition, Γ^*=____ H\K\tx)*~r*)lM*}, and M* is the secondary transient The difference from the transient current, N* is the difference between the transient current and the steady-state current, Ik* is the sum of the steady-state currents of the synchronous generator, and I, *, and 1% are the sub-transient short-circuit currents of the equivalent generator, respectively. With the transient short-circuit current, Ikd is the initial short-circuit current of the synchronous motor, r, kd and rkd are the secondary initial short-circuit current and the transient initial short-circuit current of the synchronous motor respectively, 〗 〖M is the secondary transient of the asynchronous motor The current, K" is the calculation constant of the equivalent generator secondary transient time parameter, T''d* and T'd* are the secondary transient time constant and transient time constant of the equivalent generator respectively, and the t S short circuit starts. Period, tx is the defined short-circuit start period, IacG is the symmetrical short-circuit current component fed to the synchronous motor, the short-circuit current non-periodic component fed to the generator, Iac4 IdcM: symmetrical and non-periodic short-circuit current of the equivalent motor feed . Finally, an output result group is output as shown in step 18, and as shown in step 19, the detection is ended. In the preferred embodiment, the round-out result group includes: a group of device symmetrical short-circuit current, a group device peak short-circuit power-group fault point symmetrical short-circuit current, and a group fault point peak (four) power ^' must be supplemented It is noted that the ship short-circuit current detecting method of the present invention is in the above-mentioned 13 201043532 preferred embodiment, and only the current detection of a generator, a transformer device or a motor is taken as an example. However, in actual operation In the above, the plurality of generators, transformers or motors can be detected at the same time. The number of such tests is easily influenced by those having relevant backgrounds and should not be limited by the specific examples of the preferred embodiment. Here, in order to further explain the effects of the present invention, the following will include a generator, an emergency generator, a transformer device, and a motor group. Taking multiple sets of fault points (numbered MG, MEG, MA, MB, MC MD, ME, MF, ΜΗ, MI, MJ, and MK) as an example to perform actual detection through the ship short-circuit current detecting method of the present invention. Analysis, the above related input data are shown in Figures 12 to 17 and Figures 18a to i8h, and the related output result groups are as shown in Figures 19a to 9d. ~and. When we compare the output group of y with the relevant data calculated by the current system, we can get the following advantages of the invention: ▲ (1) Considering the generator load effect and AC component before ignoring the fault The transient attenuation, the motor energy conversion efficiency, the short-circuit current fed by the shaft power generation system, and the influence of the cable operating temperature, etc., result in a more accurate and actual short-circuit current. (2) The calculated short-circuit current results are large, and such a conservative estimation results in a large short-circuit load capacity for the design of the ship power system, and reduces the damage risk caused by the short-circuit current. (2) Raising the system voltage, which is very significant for reducing the short-circuit current. As a result, the volume and weight of the ship-related protection switchgear can be reduced, which will help the planning of the ship's power protection equipment. design. In summary, the ship short-circuit current detecting method of the present invention can achieve the object of the present invention. However, the above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, that is, the simple equivalent changes and modifications made by the scope of the present invention and the description of the invention. All remain within the scope of the invention patent. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flow chart illustrating the implementation steps of a preferred embodiment of the ship short-circuit current detecting method of the present invention; FIG. 2 is a schematic diagram showing the input of a human-machine interface in the preferred embodiment. Fig. 3 is a schematic diagram showing a generator parameter input page in the preferred embodiment; Fig. 4 is a schematic view showing a transformer parameter input page in the preferred embodiment; Ο Fig. 5 is a schematic view In the preferred embodiment, the motor parameter input page is shown; FIG. 6 is a schematic view showing a bus bar voltage input page in the preferred embodiment; FIG. 7 is a schematic view showing the preferred embodiment. A line impedance input page; FIG. 8 is a schematic diagram showing a transformer line parameter input page in the preferred embodiment; 15 201043532 Fault point line diagram 9 is a schematic diagram illustrating the road parameter input page in the preferred embodiment Figure 10 is a schematic diagram showing the preferred embodiment of the parameter input page; cable impedance diagram 11 is a schematic diagram illustrating the preferred embodiment, - parameters Into the page; T motor basic, two: and Figs. 18a to 18h are schematic diagrams showing the relevant input data of the keys when the actual detection of the short-circuit current detecting method of the ship is described in the preferred embodiment; and 1 19 A to FIG. 19d are schematic diagrams showing the actual-rounding result group of the ship short-circuit current detecting method in the preferred embodiment of the present invention. “ 异 16 201043532 [Description of main component symbols] 11~18····Steps 151~153 steps 121~122 steps ❹

17

Claims (1)

201043532 VII. Patent application scope: 1 · A ship short-circuit current detection method, comprising the following steps: (a) inputting an input data group; (b) establishing a set of impedance values; (c) calculating a generator and a motor current; d) Calculate the bus bar synthesis parameters; (e) Calculate the bus bar synthesis current; and (0 output one output result group. 2. According to the application scope of the scope of the ship short-circuit current detection method 'where 'in the a) In the step, the input data group includes a set of basic equipment data, a set of transformer line parameters, a set of fault point line parameters, and a set of basic line parameters. 3. The ship according to item 2 of the patent application scope. The short-circuit current detecting method, wherein, in the step (a), the basic data of the group of devices in the input data group includes a generator apparent power, a generator rated voltage, a generator secondary transient reactance, and a Generator transient reactance, generator reactance, one generator transient time constant, one generator transient time constant, one generator DC time constant, one generator Stator resistance, a generator frequency, a generator rated current ratio, a generator power factor, a transformer apparent power, a transformer primary voltage, a transformer secondary voltage, a transformer internal resistance, a transformer internal reactance, A motor operating state value, - total motor power, - motor apparent power, a motor rated current, a motor short circuit current AC component, a motor short circuit muscle value / claw forming knife, a motor short circuit current peak, a bus voltage Group 18 201043532 'and a line impedance value group β 4. The ship short-circuit current detecting method according to claim 2, wherein in the step (a), the set of transformer lines in the input data group The parameters include: transformer primary measuring line diameter, one transformer secondary measuring line diameter, - transformer line parallel quantity, and one transformer line length. 5. According to the patent application scope item 2, the ship short-circuit current detecting method 〇 〇 In the step (a), the set of fault point line parameter packets in the input data group - the line diameter of the fault point, the number of parallel lines of the fault point and the length of the line of a fault point. 6. According to the method for detecting the short-circuit current of the ship according to item 2 of the patent scope of the patent, 'in the step (4), the input The basic parameters of the group of lines in the data group include a line resistance value and a line reactance value. 7. According to the ship short-circuit current detection method described in item 2 of the patent scope, wherein the power is in the step (4) The input data group required for the operation of the device impedance calculation module further includes a set of motor parameters, and the set of motor parameters has a motor rated voltage, a motor frequency, a motor rated current, a motor power factor, a motor rotor resistance, A motor stator resistance, a motor rotor reactance, a motor stator reactance, a total motor reactance, a motor line port length, a motor line length, a motor line parallel number, a motor line resistance, and a motor line reactance. Voltage changer motor change (4) reactance, - motor change _ one test 8. According to the patent application scope item 7, the short-circuit current detection method, wherein, in the (4) (four) towel, the motor reference (four) has - motor variable 19 201043532 Constant voltage, and a motor transformer secondary rated voltage. 9. The ship short-circuit current detecting method according to item ith or item 2 of the patent application, wherein in the step (f), the output result group comprises a set of device symmetrical short-circuit currents, a set of device peak short-circuit currents A set of fault point symmetrical short-circuit currents, and a set of fault point peak short-circuit currents. 10. The method for detecting short-circuit current of a ship according to any one of clauses 2 to 9 of the patent application, wherein in the step (b), the set of impedance values is calculated according to the following manner: Multiply the line resistance by the length of the line and divide by the number of lines in parallel, and then divide by 1 〇〇〇 to get the resistance value. Then multiply the line reactance by the length of the line and divide by the number of lines connected in parallel, and then divide by 1000. Output voltage value. 11. The method for detecting short-circuit current of a ship according to item 丨0 of the patent application scope, wherein in the step (C), the calculation of the generator and the motor current T<kM xM {Rs+R) , _K_. = El[(RR+Rs+Rf+(X7+Xs+W\ A Cos Φμ ~ RmKm ' Em = y J j 1/2 yT1 2 sin Φι^ M ^ rM 'and Z"M is the sub-transient impedance of the non-synchronous motor, Rr is the rotor resistance of the non-synchronous motor, Rs is the stator resistance of the non-synchronous motor, and R is the generator 20 1 acM=^ >-2IrM ' ldcM(t) = yi2(rM-irM sin^M)e~t/TdcM Λ IpM=SIrM ' 2 I〇cM{t) = r'M e~IIT^ IpM(t) = ^ 2IacM(t) + IdcM(ty V\ °> rRR 201043532 The resistance to the line of the main bus system, x is the reactance of the line generating the power, xR is the stator reactance of the non-synchronous motor bus bar step motor, 1' is asynchronous The second Xs of the motor is a non-identical, long τ, and the secondary transient short circuit of the motor The symmetrical short-circuit current fed by the equivalent motor is the equivalent motor rated current, 1PM is the maximum asymmetric short-circuit current, T, M is the sub-transient time constant, TdeM is the DC time constant, and χΜ is the non-synchronous motor. Reactance, called ",", ^ and E, M are the secondary transient and transient internal potential of the short-circuit instant motor, SIN ~ and c〇s❼ are motor power factor, z', M is the second asynchronous motor Transient impedance, UrM is the motor's front voltage, and IdcM is the non-periodic short-circuit current fed by the equivalent motor. 12. The ship short-circuit current detecting method according to claim 11, wherein in the step (d), the bus bar synthesis parameter is calculated as follows: ^ac =^£<7! +JacG2 +' " + IacG„ +^acMl +IacM2 +'" + IacMm , Ip =IpGx +IpG2 +'" + 1pGn +IpMx +IpM2 +'" + IpMm ' 1 ac_MGi =Iac ~1acGi for i=l To n, 'for i=l to m ' lacG^TO =Σ^σ(〇+ Σ^αοΜ(0 , 1 dcG (〇ΓΟ = Σ ^ dcG (Ο + ΣI dcM (〇, Z*=-yjR* +X* , X*=yjzl2-Ri , X* =^Z*-Ri , Z*^^R*+X* , Rg = Rcp + Rt + Res ' Xe=Xcp+Xt+^'cs ' X*= ^2-R*, X* =^z}-r} 'x: =W:'z: z* =~^l' x*= , z: Si* r'Z. Z: λ/Ϊ+? , Ks=Kj^f, Xcs=xcsx(j^f, is=IpX(才, , and Z''* and Z'* 21 201043532 The secondary transient impedance and transient impedance of the equivalent generator, U〇 is the line voltage of the fault, f is the frequency of the generator, e3 is the number of abnormalities of the equivalent sub-transient reactance, I* is the equivalent generator current, and 匕 and ί% are the equivalent generators respectively. Transient short-circuit current and transient short-circuit current, R* is equivalent generator resistance, Tde· is the number of hours of non-periodic component, X· is equivalent generator reactance, X′ and χ′* are equivalent generators respectively The secondary transient reactance and transient reactance, Z* is the equivalent generator impedance, Iae is the main bus fault point, • the ten-way Newway electric 々, L, IacGi n is the synchronous motor short-circuit current AC forming knife IacM1~ m is the symmetrical short-circuit current of the non-synchronous motor, Ip is the maximum asymmetric short-circuit current of the main bus fault point, Ιρ_ is the synchronous rotor sub-short current component, IpMi m is the non-synchronous motor asymmetric road motor component, iae— MGi and Ip MGi are respectively symmetrical for any fault point, and the maximum asymmetric bridge current, IdeG is the short circuit fed by the generator. The non-periodic components of the flow, IacM and IdeM are the symmetrical and aperiodic short-circuit currents fed by the equivalent motor, the secondary transient short-circuit current and the transient short-circuit current of the n 1%-equivalent equivalent generator, respectively. Person measurement and _ sub-measurement M, t is the short-circuit start period, ^ and R, divided into X measurement and conversion to the secondary measurement of the line resistance, all the power equipment resistance algebra between the main bus and the fault point And Rt is the transformer 11 resistor Ί the main bus and the fault point between all the power equipment reactance generation 22 201043532 number and Xcp and X'cs respectively for the first measurement and conversion to the second measurement line reactance, Xt is Transformer reactance, Is is the transformer secondary current 13. According to the patent scope of the 12th ship short-circuit current detection method 'where' in the (e) step, the bus bar synthesis current is calculated as follows 1 * I * , N* U , I* t'Lpkdi, h*^Ikdi ' K = ~Ikd)e~t/Td* +Ikd, ^ K'\t) = M*e~t/Td* +I:, 〇 , IacG(tx>=M^^+N^^+I^, /』λ=ς:ά),+ς;,』), ,^0[;7 post 1);+^(recognition, 7 = you e4/rrfc*, T Shanghai = —t x HldcG(tx)J^2rt] r<,*Tn{[/acG(i;c)( -(M.e^~rd* +Ikt)jnr} And M* is the difference between the secondary transient and the transient current, N* is the transient current and the steady state electric grab difference, Ik* is the sum of the steady state current of the synchronous generator, p, * and p* are respectively equivalent The secondary transient short-circuit current of the generator and the transient short-circuit current, h is the initial short-circuit current of the synchronous motor, and ~ and ~ are respectively synchronized: the secondary transient initial short-circuit current and the transient initial short-circuit current, flow, I, = The secondary transient short-circuit current of the step motor, κ" is the # abnormal number of the equivalent generator, and the rv and m are equivalent: the temporary f time constant and the transient time constant, and t is the short circuit. During the start, =:m path start period, 1 a. The synchronous component fed to the synchronous motor: IdeG is the non-periodic periodic short of the short-circuit current fed by the generator. _ respectively is the symmetrical and non-equal of the equivalent motor feed 23 201043532 14· According to the patent application scope i3, wherein in the step (c), before the calculation of the ship short-circuit current detecting method flow, first determine the desired start, and the generator and the motor are electrically connected to (10)+ Tile, if it is, then H nose - the total power of the motor is large ZV = (U6 押., ^ = 〇·ΐ5ρ 々大1 motor, and set 疋· &=_ wind, ~=刚兴, and -RS+尺R=〇.〇55p.u.,不不· and set w ·,; ^ then determine that the motor is a small motor, _ _ 88P'U' rS = ^-043p, u. > rR = 0.027pu, and rM = & +4 = 〇. 〇 7 ,, M is Sub-transient impedance of non-synchronous motor, χΜ is sub-transient, Rr4 machine rotor resistance, Rs is non-synchronous motor stator resistance, ~ is motor resistance. S is 15_ ship short-circuit current according to the application scope of the M-th bucket The detection method further comprises - step (g) before the step (4), clearing the previously calculated input and the result content. 16. The ship short-circuit current detecting method according to the patent application _15 is further included - located in the g) Step (8) before the step, pre-setting at least one number required for the test. 17. According to the method for detecting short-circuit current of the ship according to item 6 of the claim patent, further comprising a step (g) and the h) Step (1) between steps to determine whether the number of generators to be detected is less than i, and if so, display - error message and Beam detector, if not, then the next step. 24