CN102879676B - A kind of reaying protection test instrument based on embedded system and the method for inspection thereof - Google Patents

Abstract

The invention discloses a kind of reaying protection test instrument based on embedded system and the method for inspection thereof, this test instrument comprises based on the embedded system of ARM11, display screen, key mouse equipment, printer, GPS locating device and GPRS communication interface, and the described embedded system based on ARM11 is connected with display screen, key mouse equipment, printer, GPS locating device and GPRS communication interface respectively; Embedded system based on ARM11 is controlled power power-supply by USB or Ethernet interface, and connects protective relaying device by RS232 interface.The present invention can experiment with computing electric current, controls reaying protection test device output test electric current, by data after device panel RS232 mouth receiving action after device action to be protected, and result and theoretical value is compared, judge that whether action is correct.After using reaying protection test instrument of the present invention, each main transformer protection time between predetermined repairs on average can shorten 1 hour.

Description

A kind of reaying protection test instrument based on embedded system and the method for inspection thereof

Technical field

The invention belongs to technical field of relay protection, relate to the proving installation of a kind of contrast ratio braking protection, especially a kind of reaying protection test instrument based on embedded system and the method for inspection thereof.

Background technology

Existing testing to relay protection ratio brake generally adopts manual method; namely the relay-protection tester of general utility functions is used; the electric parameter that the setting of simulated failure situation exports; the action situation of monitoring and protecting device; correctly whether checking defencive function and customization setting, are recorded in assay in debugging report then.

The existing this method of inspection comes with some shortcomings part:

The technical capability of undue dependence staff individual.Field personnel fully must understand ratio brake checking function, shifts onto calculate its acting characteristic according to protection definite value parameter, then could simulated failure inspection action situation.Single manufacturer due to protective device and model numerous, just require staff to be familiar with and remember a large amount of knowledge, and will along with the upgrading of manufacturer synchronized update, this had both improve the requirement to individual manpower, also easily caused confusion and made mistakes.Need spended time to go to be familiar with tester simultaneously.Performance parameter and the using method of different tester are different, and instrument adopts the software and hardware structure of embedded programmable mostly at present, and function upgrading speed is fast.Once change, spended time goes the method for operating of familiar a set of new system again again, both brings inconvenience to work on the spot, and wastes a large amount of time.

Manual record acting characteristic: after protective device action, uses printer that protection message is directly exported printing usually, or artificial from device display screen reading operation value.

Data mode disunity: tester, after carrying out a function test, often generates the data drawing list of a user-defined format, the form that different testers exports is different.Staff or manually therefrom must copy out data and rearrange, or can only to paste its chart as annex, and directly cannot generate the debugging report file of upper-level leader's required standard form.

Summary of the invention

The object of the invention is to the shortcoming overcoming above-mentioned prior art; a kind of reaying protection test instrument based on embedded system is provided; this reaying protection test instrument can experiment with computing electric current; control reaying protection test device output test electric current; by data after device panel RS232 mouth receiving action after device action to be protected; and result and theoretical value are compared, judge that whether action is correct.

The object of the invention is to solve by the following technical programs:

This reaying protection test instrument based on embedded system, comprise based on the embedded system of ARM11, display screen, key mouse equipment, printer, GPS locating device and GPRS communication interface, the described embedded system based on ARM11 is connected with display screen, key mouse equipment, printer, GPS locating device and GPRS communication interface respectively; Embedded system based on ARM11 is controlled power power-supply by USB or Ethernet interface, and connects protective relaying device by RS232 interface.

The above-mentioned embedded system based on ARM11 adopts 6410 development boards for exploitation basis; Upper strata embedded system adopts Windows CE as its operating system.

Above-mentioned display screen is 10 cun of tangible display screens of the very color LCD of TFT.

Above-mentioned key mouse equipment is the track ball mouse and keyboard expanded by USB interface.

The present invention also proposes a kind of method of inspection based on above-mentioned reaying protection test instrument, is specially:

1) first according to the electric pressure of protective relaying device, each group of current value of this device ratio brake curve and adding apparatus is calculated; According to protection philosophy, the Adding Way of determining device each side electric current;

2) the test current data then will calculated, export power supply to, and add stream to protective relaying device; Before test starts, after test condition is provided with, start to control power power-supply output current; Sent by reaying protection test instrument and represent that the data of three-phase current input to its power power-supply, three-phase current analog quantity is exported, simultaneously to the process that electric current automatically improves or reduces, until protection act by power power-supply, return contact is connected, and stops the output of electric current;

3) reaying protection test instrument constantly gathers the feedback signal of protective relaying device by RS232 interface, and processes accordingly according to the action behavior of the protective relaying device of feedback, switch data district or interrupt procedure; Receive the action report of protective relaying device, comprising difference current during action, stalling current; In process of the test, arrange corresponding zone bit according to the action message of protective relaying device, the condition meeting setting just exits from test, process test findings; Now, system obtains a point on percentage differential curve; By repeatedly adding stream, course of action, system obtains multiple operating point; According to these points, system draws out theory and practice percentage differential curve respectively, and carries out comparative analysis; Picture display or printer printout are selected in the output of test findings.

Further, transformer each side current and phase difference and balanced compensated as follows:

1) current transformer TA mode of connection

The each side TA of transformer adopts totally Y wiring, and secondary current directly accesses reaying protection test instrument; Each side phase current TA is all positive ends with bus bar side;

2) calculating of coefficient of balance

Calculating transformer one time, each side rated current I _1n:

$I_{1n}=\frac{S_n}{\sqrt{3}{U}_{1n}}$

In formula: S _nfor the maximum rated capacity of transformer; U _1nfor transformer rated primary voltage; Calculating transformer each side secondary rated current I _2n:

$I_{2n}=\frac{I_{1n}}{n_{\mathrm{TA}}}$

In formula: I _2nfor transformer each side secondary rated current; I _1nfor transformer one time, each side rated current; n _tAfor transformer each side TA no-load voltage ratio;

Be benchmark with high-pressure side, in calculating transformer, low-pressure side coefficient of balance:

$K_{\mathrm{phM}}=\frac{I_{2\mathrm{nH}}}{I_{2\mathrm{nM}}}=\frac{I_{1\mathrm{nH}}/n_{\mathrm{TAH}}}{I_{1\mathrm{nM}}/n_{\mathrm{TAM}}}=\frac{S_n/\sqrt{3}{U}_{1\mathrm{nH}}}{S_n/\sqrt{3}{U}_{1\mathrm{nM}}}\·\frac{n_{\mathrm{TAM}}}{n_{\mathrm{TAH}}}=\frac{U_{1\mathrm{nM}}}{U_{1\mathrm{nH}}}\·\frac{n_{\mathrm{TAM}}}{n_{\mathrm{TAH}}}$

$K_{\mathrm{phL}}=\frac{U_{1\mathrm{nL}}}{U_{1\mathrm{nH}}},\frac{n_{\mathrm{TAL}}}{n_{\mathrm{TAH}}}$

In formula: K _phMfor transformer medium voltage side coefficient of balance; K _phLfor low-pressure side coefficient of balance.

By in, each phase current of low-pressure side is multiplied with corresponding coefficient of balance, obtains each phase current after amplitude compensation;

3) each side current phase compensates

Transformer each side TA secondary current phase correction, adopts and carries out phase calibration in Y side.

The present invention has following beneficial effect:

Reaying protection test instrument of the present invention reduces the requirement of tester, improves testing efficiency, it also avoid due to select method of testing improper and produce test errors.The present invention makes relay protection test process more intelligent, robotization, shortens power off time, reduces labour intensity and thinks and the interference of factor improve reliability and the accuracy of test.After using reaying protection test instrument of the present invention, each main transformer protection time between predetermined repairs on average can shorten 1 hour.

Accompanying drawing explanation

Fig. 1 is reaying protection test instrument structured flowchart of the present invention;

Fig. 2 is ratio-restrained characteristic curve.

Embodiment

Below in conjunction with accompanying drawing, the present invention is described in further detail:

See Fig. 1, the present invention is based on the reaying protection test instrument of embedded system, comprise based on the embedded system of ARM11, display screen, key mouse equipment, printer, GPS locating device and GPRS communication interface, the described embedded system based on ARM11 is connected with display screen, key mouse equipment, printer, GPS locating device and GPRS communication interface respectively; Embedded system based on ARM11 is controlled power power-supply by USB or Ethernet interface, and connects protective relaying device by RS232 interface.

The wherein said embedded system based on ARM11 adopts 6410 development boards for exploitation basis; 6410 is a development platforms of 16/32 RSIC microprocessor S3C6410X based on SAMSUNG, and S3C6410X is the general processor for the terminal device such as hand-held, mobile based on ARM1176JZF-S core.S3C6410 is a low-power, high performance-price ratio, high performance for mobile phone and general procedure RSIC processor.For 2.5G and 3G communication service provides the hardware performance of optimization, adopt the internal bus framework of 64/32bit, merged AXI, AHB, APB bus.S3C6410 comprises the external memory interface of optimization, and this interface can meet the data bandwidth requirement in high-end communication service.Interface is divided into two-way, DRAM and Flash/ROM/DRAM port.DRAM port can support Mobile DDR, DDR, MobileSDRAM, SDRAM by configuration.Flash/ROM/DRAM port supports arbitrary MobileDDR, DDR, Mobile SDRAM, SDRAM storer of external memory storage of the types such as NOR-Flash, NAND-Flash, OneNAND, CF, ROM.In order to reduce the cost of whole system and promote general function, S3C6410 comprises a lot of hardware capability peripheral hardware: Camera interface, TFT 24bit true color lcd controller, System Management Unit (power supply all the time etc.), the UART of 4 passages, the DMA of 32 passages, 4 passage timers, universaling I/O port, I2S bus, I2C bus, USB Host, the pll clock generator of high speed USB OTG, SD Host and high speed mmc card interface and inside.ARMSYS 6410 development board provides LCD interface, TVout interface, camera input interface, 4 road serial ports, the 1 infrared mouth in tunnel, 2 road SD card interfaces, 1 road CF card interface, 1 road 10/100M network interface, 1 road USB2.0-OTG, 1 road USB Host, there is higher dominant frequency and more enrich peripheral hardware, embedded system application scenario performance and processing power being had to requirements at the higher level can be applicable to.Upper strata embedded system adopts Windows CE as its operating system, mainly considers that this operating system security is stablized, powerful.In order to extender design and secondary development, the present invention also provides abundant software development environment, as Integrated Development Environment such as VC++, EVC.Operating system and the various user software of built-in industrial control machine are all installed to SD card, make this microcomputer protective relay analyzer have more compact structure like this, and IDE hard disk is not only installed simple and easy relatively, and can alleviate the weight of analyzer, easy to carry.

Display screen of the present invention adopts the tangible display screen of the very color LCD of 10 cun of TFT of main flow as graphic display interface; the track ball mouse expanded by USB interface and optimization keyboard, as the keyboard and mouse on reaying protection test instrument panel, separately provide the Extended Capabilities Port of other interfaces such as serial ports with for subsequent use.Consider the networking tendency of power system device from now on, native system provides the interface such as standard ethernet, GPRS simultaneously, and being convenient to this reaying protection test instrument can carry out network service.

Based on above reaying protection test instrument, the present invention proposes a kind of method of inspection, specific as follows:

1) first according to the electric pressure of protective relaying device, test instrument calculates each group of current value of this device ratio brake curve and adding apparatus; According to protection philosophy, the Adding Way of determining device each side electric current;

Test instrument draws together four parts: the calculating of CSC-326FB transformer differential protection percentage differential, AccessPort, the process of serial ports message analysis, ratio brake Calculation results compare.

Ratio brake parameter calculates and comprises parameters input, intermediate parameters, the calculating of ratio brake point and characteristic graphic representations parts.

Parameters input part: this part needs the parameter of input to comprise: the mode of connection, high-pressure side rated voltage, medium voltage side rated voltage, low-pressure side rated voltage, high-pressure side TA no-load voltage ratio, medium voltage side TA no-load voltage ratio, low-pressure side TA no-load voltage ratio, main transformer capacity, differential starting current, differential quick-break electric current, slope (KID).

Intermediate parameters comprises: high-pressure side regulation coefficient, medium voltage side regulation coefficient, low-pressure side regulation coefficient, high-pressure side rated current.By the setting of parameter, test instrument calculates intermediate parameters automatically.Ratio-restrained characteristic visuals draws out percentage differential family curve according to the parameter inputted, result of calculation simultaneously.In addition, the intermediate parameters calculated can be saved to file.

Percentage differential point calculating section: first this part needs to input the selection of ratio brake both sides, its have height-low, high-in, in-low three kinds of selections.By selecting different both sides, test instrument automatic decision computing formula.Test instrument also needs the calculation level of input brake electric current, according to calculation level, automatically calculates theoretical differential current value, and the size of current added needed for high-pressure side.When carrying out the calculating of multiple current point, family curve correspondingly can be drawn out the position of calculation level.

2) the test current data then will calculated, export power supply to, and add stream to protective relaying device; Before test starts, after test condition is provided with, start to control power power-supply output current; Sent by reaying protection test instrument and represent that the data of three-phase current input to its power power-supply, three-phase current analog quantity is exported, simultaneously to the process that electric current automatically improves or reduces, until protection act by power power-supply, return contact is connected, and stops the output of electric current;

Biased differential protection characteristic: adopt conventional syllogic broken line, is shown in the ratio-restrained characteristic curve of Fig. 2.

Transformer each side current and phase difference and balanced compensated:

1) current transformer (TA) mode of connection

The each side TA of transformer adopts totally Y wiring, and secondary current directly accesses reaying protection test instrument; Each side phase current TA is all positive ends with bus bar side;

2) calculating of coefficient of balance

Calculating transformer one time, each side rated current I _1n:

$I_{1n}=\frac{S_n}{\sqrt{3}{U}_{1n}}$

In formula: S _nfor the maximum rated capacity of transformer; U _1nfor transformer rated primary voltage;

Calculating transformer each side secondary rated current I _2n:

$I_{2n}=\frac{I_{1n}}{n_{\mathrm{TA}}}$

In formula: I _2nfor transformer each side secondary rated current; I _1nfor transformer one time, each side rated current; n _tAfor transformer each side TA no-load voltage ratio;

Be benchmark with high-pressure side, in calculating transformer, low-pressure side coefficient of balance:

$K_{\mathrm{phM}}=\frac{I_{2\mathrm{nH}}}{I_{2\mathrm{nM}}}=\frac{I_{1\mathrm{nH}}/n_{\mathrm{TAH}}}{I_{1\mathrm{nM}}/n_{\mathrm{TAM}}}=\frac{S_n/\sqrt{3}{U}_{1\mathrm{nH}}}{S_n/\sqrt{3}{U}_{1\mathrm{nM}}}\·\frac{n_{\mathrm{TAM}}}{n_{\mathrm{TAH}}}=\frac{U_{1\mathrm{nM}}}{U_{1\mathrm{nH}}}\·\frac{n_{\mathrm{TAM}}}{n_{\mathrm{TAH}}}$

$K_{\mathrm{phL}}=\frac{U_{1\mathrm{nL}}}{U_{1\mathrm{nH}}},\frac{n_{\mathrm{TAL}}}{n_{\mathrm{TAH}}}$

In formula: K _phMfor transformer medium voltage side coefficient of balance; K _phLfor low-pressure side coefficient of balance.

By in, each phase current of low-pressure side is multiplied with corresponding coefficient of balance, obtains each phase current after amplitude compensation;

3) each side current phase compensates

Transformer each side TA secondary current phase correction, adopts and carries out phase calibration in Y side.

Such as

The wiring of Y0/ Δ-11, its bearing calibration is as follows:

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_A=({\stackrel{\·}{I}}_A-{\stackrel{\·}{I}}_B)/\sqrt{3}\\ {\stackrel{\·}{I}}_B=\left({\stackrel{\·}{I}}_B{-{\stackrel{\·}{I}}_C}_{}\right)/\sqrt{3}\\ {\stackrel{\·}{I}}_C=({\stackrel{\·}{I}}_C-{\stackrel{\·}{I}}_A)/\sqrt{3}\end{array}\right.$

In formula: I _a, I _b, I _cfor Y side TA secondary current; I ' _a, I ' _b, I ' _c' be each phase current after the correction of Y side.Other mode of connection can be analogized.In device by " wiring of middle pressure winding triangle ", " wiring of low pressure winding triangle ", " software do not do TA wiring star triangle conversion " control word and " mode of connection hour number " definite value to select the mode of connection.The correlation computations of difference current and stalling current, be all current phase correction and balanced compensated after basis on carry out.

The computing method of difference current and stalling current:

The computing method of difference current and stalling current are as follows:

$\left\{\begin{array}{c}{I}_{\mathrm{dz}}=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{\stackrel{\·}{I}}_i\\ I_{\mathrm{zd}}=\frac{1}{2}|{\stackrel{\·}{I}}_{\max }-\mathrm{\Σ}{\stackrel{\·}{I}}_i|\end{array}\right.$

In formula: I _dzfor difference current; I _zdfor stalling current; for all sides phase current sum; for phase current maximum in all sides; for other side (except maximum phase current side) phase current sum.

Operating criterion

The operating criterion of biased differential protection is as follows:

$\left\{\begin{array}{cc}{I}_{\mathrm{dz}}\≥K_{b1}{I}_{\mathrm{zd}}+I_{\mathrm{CD}}& I_{\mathrm{zd}}\≤{0.6I}_e\\ I_{\mathrm{dz}}\≥\mathrm{KID}(I_{\mathrm{zd}}-{0.6I}_e)+K_{b1}\×{0.6I}_e+I_{\mathrm{CD}}& {0.6I}_e\≤I_{\mathrm{zd}}\≤{5I}_e\\ I_{\mathrm{dz}}\≥K_{b3}(I_{\mathrm{zd}}-{5I}_e)+\mathrm{KID}({5I}_e-{0.6I}_e)+K_{b1}\×{0.6I}_e+I_{\mathrm{CD}}& {5I}_e\≤I_{\mathrm{zd}}\end{array}\right.$

In formula: I _cDfor differential protection current ration; I _dzfor difference current; I _zdfor stalling current; K _b1for the slope (fixedly getting 0.2) of first paragraph broken line; KID is that its value of slope of second segment broken line equals proportional brake coefficient definite value; K _b3it is the slope (fixedly getting 0.7) of the 3rd section of broken line.

By differentiating mutually, arbitrary when meeting above condition mutually, biased differential protection action.Biased differential protection exports after magnetizing inrush current discrimination, TA broken string differentiation (can select).

Balanced balanced current method of testing

Each side CT all by Y connection, and requires that each side CT all gets involved by same polarity, and namely each side electric current is all to flow into (or outflow) transformer for positive dirction.Carry out phase correction to the electric current of transformer Y shape side, its effect is identical with CT being pressed the wiring of △ shape.The Current Transformer Secondary current phase adjustment of CSC-326FB main transformer protection transformer each side is benchmark with Y, adopts the mapping mode of △ → Y, adjustment current balance type.

For the i-th side, its difference current is by following formulae discovery:

$\left\{\begin{array}{c}{I}_{\mathrm{da}}=(I_{1\mathrm{ab}}+I_{2\mathrm{ab}}+I_{3a})\·k_i\\ I_{\mathrm{db}}=(I_{1\mathrm{bc}}+I_{2\mathrm{bc}}+I_{3b})\·k_i\\ I_{\mathrm{dc}}=(I_{1\mathrm{ca}}+I_{2\mathrm{ca}}+I_{3c})\·k_i\end{array}\right.---\left(1\right)$

Wherein, I _ia, I _ib, I _icit is the CT secondary current of the i-th side; I _da, I _db, I _dcfor each phase current after conversion and angular transformation; k _ifor the i side CT voltage ratio control coefficient determined by transformer rated capacity, each side rated voltage, current transformer ratio.

The calculating of CT voltage ratio control coefficient is with the first side for benchmark, and namely putting the first side CT voltage ratio control coefficient is 1, and other sides CT voltage ratio control coefficient calculation method is as follows:

In formula: U _nxfor xth side rated line voltage, K _cTxfor no-load voltage ratio, the K of xth side CT _jxfor transformer xth side winding connection coefficient, (suppose each side CT all with Y shape access differential protection, transformer xth side winding is Y K when connecing _jx=1, when △ connects ).

As can be seen from formula (1), be only added to electric current I at Y side A (B) (C) _1atime, not only can produce difference current mutually at A (B) (C), the differential protection due to transformer is that phase-splitting is differential, and this just may cause other separately reach difference current definite value and action occurs, cannot make A phase ratio-restrained characteristic.Therefore, it is the most critical factor of carrying out the test of ratio-restrained characteristic curve that the difference current how making it produce in an other phase is eliminated.

Analysis mode (1) is known, when transformer is added to electric current I at A (B) (C), draws I by formulae discovery _da=I, I _db=0, I _dc=I.When doing the test of Y-△ ratio-restrained characteristic curve, electric current I can be added in the C phase of △ side, the difference stream I that it is produced _dci is flowed with the difference produced in C phase after Y side A is added to electric current _dcequal and opposite in direction, direction is contrary, C is differed mobile equilibrium, makes C phase difference current become 0, so just can by fixing Y side Ia, conversion △ side I _3asize be made at different I easily _3aunder ratio-restrained characteristic, would not occur that C phase differential action causes making the situation of A phase ratio braking.In like manner, by this current-balance method, B, C phase can be made easily and obtain ratio-restrained characteristic.

From formula (1), when carrying out current balance type, because the difference after Y side corrects with △ side flows all relevant with CT voltage ratio control coefficient, therefore when carrying out current balance type, the impact of CT voltage ratio control coefficient should be considered, as being added to electric current I at Y side A _1catime, at the balanced balanced current I that △ side C is added to _3cfor

I _dc=I _1ca·k ₁=I _3c·k ₃

→I _3c=·I _1ca/·k ₃(3)

Can calculate when Y side adds electric current easily by formula (1), the balanced balanced current value added in △ side.In like manner can release when other are added electric current, at the balanced balanced current that △ side adds.

Balanced balanced current method testing procedure

General relay-protection tester can provide 3 electric currents, and therefore when testing, test to add single-phase or biphase current only in the every side of protective device.Based on this, the step of test rate braking characteristic curve is as follows:

1. calculate each lateral balance coefficient k according to transformer parameter _i;

2. be added to electric current I at Y side A _1a, calculate corresponding I by formula (3) _1abalanced balanced current I _3c, add △ side C phase to balance I _1athe difference stream I produced in C phase _dc.

3. be added to I at △ side A _3a, direction and I _1aon the contrary, constantly I is changed _1aamplitude, direction is constant, obtain correspond to I _1aa braking point under value.Different I will be corresponded to _1aunder

Braking point couples together, and is exactly ratio-restrained characteristic curve.

3) reaying protection test instrument constantly gathers the feedback signal of protective relaying device by RS232 interface, and processes accordingly according to the action behavior of the protective relaying device of feedback, switch data district or interrupt procedure; Receive the action report of protective relaying device, comprising difference current during action, stalling current; In process of the test, arrange corresponding zone bit according to the action message of protective relaying device, the condition meeting setting just exits from test, process test findings; Now, system obtains a point on percentage differential curve; By repeatedly adding stream, course of action, system obtains multiple operating point; According to these points, system draws out theory and practice percentage differential curve respectively, and carries out comparative analysis; Picture display or printer printout are selected in the output of test findings.

AccessPort is in wait data phase after starting.When after protective device identification, the data in file are read message receiving element by test instrument automatically, filter, and the message of related actions event in message is shown to data receiver window.The difference current of action event and the size of stalling current in extracting in the message obtained by filtration.The size of difference current, stalling current all can extract.

The graphical display function of test instrument can draw ratio-restrained characteristic curve, theoretical test point and actual act point.

Claims (4)

1. the method for inspection of a reaying protection test instrument, described reaying protection test instrument comprises based on the embedded system of ARM11, display screen, key mouse equipment, printer, GPS locating device and GPRS communication interface, and the described embedded system based on ARM11 is connected with display screen, key mouse equipment, printer, GPS locating device and GPRS communication interface respectively; Embedded system based on ARM11 is controlled power power-supply by USB or Ethernet interface, and connects protective relaying device by RS232 interface; It is characterized in that, comprise the following steps:

1) first according to the electric pressure of protective relaying device, each group of current value of this device ratio brake curve and adding apparatus is calculated; According to protection philosophy, the Adding Way of determining device each side electric current;

2) the test current data then will calculated, export power supply to, and add stream to protective relaying device; Before test starts, after test condition is provided with, start to control power power-supply output current; Sent by reaying protection test instrument and represent that the data of three-phase current input to its power power-supply, three-phase current analog quantity is exported, simultaneously to the process that electric current automatically improves or reduces, until protection act by power power-supply, return contact is connected, and stops the output of electric current;

3) reaying protection test instrument constantly gathers the feedback signal of protective relaying device by RS232 interface, and processes accordingly according to the action behavior of the protective relaying device of feedback, switch data district or interrupt procedure; Receive the action report of protective relaying device, comprising difference current during action, stalling current; In process of the test, arrange corresponding zone bit according to the action message of protective relaying device, the condition meeting setting just exits from test, process test findings; Now, system obtains a point on percentage differential curve; By repeatedly adding stream, course of action, system obtains multiple operating point; According to these points, system draws out theory and practice percentage differential curve respectively, and carries out comparative analysis; Picture display or printer printout are selected in the output of test findings.

2. the method for inspection of reaying protection test instrument according to claim 1, is characterized in that, the described embedded system based on ARM11 adopts 6410 development boards for exploitation basis; Upper strata embedded system adopts Windows CE as its operating system.

3. the method for inspection of reaying protection test instrument according to claim 1, is characterized in that, described display screen is 10 cun of tangible display screens of the very color LCD of TFT.

4. the method for inspection of reaying protection test instrument according to claim 1, is characterized in that, described key mouse equipment is the track ball mouse and keyboard expanded by USB interface.