Digital comparator

 

(57) Abstract:

The invention relates to computing and can be used to compare complex vector quantities. The technical result is to perform a comparison in real time. Method and device based on receiving derived from the original values, the multiplication of them, the summation of the works and the scaling of the amount received to obtain the phase difference between the source complex vector quantities. 2 C. and 23 C.p. f-crystals, 10 ill.

The present invention relates to a digital comparator to compare two complex vector quantities in real time and, in particular, to a digital comparator used in relay protection.

Relay protection usually consists of one or more of the following functions in relation to a protected power systems or power: (a) monitoring system to determine is whether the system is in normal condition or not; (b) measurements, which include the measurement of some electrical quantities; (c) protection, which usually includes a trip switch circuit upon detection of a short circuit; and (d) alarm, which besplatnih functions, such as failure detection, the determination of the direction of power flow, the detection of the maximum current and other systems of relay protection must compare two complex vector quantities (voltages and currents). Usually, the sooner such a comparison can be made, the better.

Until the present invention the protective relay has compared the complex vector values using frequency domain methods, such as the method of Fourier transform. There is a method of analysis of vector quantities in the European patent N 447575, publ. 25.09.91, CL G 06 F 15/347, according to which receive the samples, representing the values of the first and second vector quantities in the first and second points in time, Peremohy them and summed works.

Also known a digital comparator for U.S. patent N 3500322, publ. 15.05.67, CL G 06 F 7/02 containing means sampling to obtain samples in the first and second points in time, means for multiplying and summing means for summing works with the appropriate connections between them.

Known and the method of determining the phase difference described in the analyzer electrical parameters in the power system for U.S. patent N 5151866, ASS="ptx2">

The main aim of the present invention is to develop methods and devices for comparison of complex vector quantities in real time.

BRIEF DESCRIPTION OF THE INVENTION

The invention uses digital methods based on the properties of the cylindrical device (discussed below), for comparison of complex vector quantities in real time. Unsteady procedures in this description, compare complex vector magnitude faster than any previously known method.

In accordance with this invention a method of real-time and device for comparing two complex vector of values represented by the signals, referred to hereinafter as "S1", "S2", include the following operations and the means to obtain reference (S1kinstantaneous value of the first complex vector value in the first time and receive count (S2kinstantaneous value of the second complex vector value of the first point in time; and after this obtain a reference (S1k+1instantaneous value of the first complex vector magnitude for the second time and receive count (S2k+1instantaneous values of the second CONV>, B1k+1and B2k+1from S1k, S1k+1, S2k+1; and further multiplying B1kB2k+1and multiplying B2kon B1k+1to get the first piece B1kB2k+1and second compositions B2kB1k+1; and then summing the first and second compositions to obtain a sum; and finally, the scaling amount to produce the result of the calculation (Mk+1) corresponding to the phase difference, if any, between the first and second complex vector quantities. The scaling operation preferably involves multiplying the amount by a specified factor proportional to the sampling period.

The signals B1 and B2 are obtained from the inputs of the digital comparator is shown below. These input signals are referred to as "S1" and "S2". The ratio between S1 and B1 includes the values of the samples S1kand S1k-1. The ratio between S2 and B2 includes the values of the samples S2kand S2k-1. In an embodiment of the present invention below, these relations have the form:

,

,

B1k= FK2[S1k+ S1k-1- FK1 B1k-1],

B2k= FK2[S2k+ S2k-1- FK1 B2k-1],

where "RB" and "LB" are a set of constants that enhance B> and S2k-1as for S1.

In preferred versions of the present invention S1kand S2kreceive a sampling signal transmission line, a S1(t) and S2(t) represent the voltages, currents, or a combination of currents and voltages, which vary in a sinusoidal manner.

In one preferable application of the present invention, the calculation result Mk+1used to detect the presence of a failure in the transmission line. For example, the calculation result can be used to detect interfacial failure in three-phase transmission line. In this case, S1(t) and S2(t) are preferably obtained from interfacial stresses and complex currents.

In another preferable application of the result of the calculation is used to determine the failure of the phase-to-ground system three-phase transmission line. In this embodiment, the present invention S1(t) and S2(t) is preferably derived from a voltage between phase and earth and complex currents.

Another preferred application of the present invention includes the use of the computing Mk+1to determine the direction of power flow in the transmission line. Transmission line can be represented as a set Cke A, the direction of power flow (from A to B or from B to A) shall be determined by a directional device. Usually there are two types of directional devices - phase and grounded. Several types of aiming devices below. In phase directional device uses phase-to-phase voltage and complex current. Grounded directional devices are grounded directional device with offset zero sequence ground directional unit shift negative sequence and grounded directional device with a current offset. In all these devices the position of the input complex vector quantities S1 and S2 is pasapalabra in relation to each other and defines a "direct" or "reverse" direction of power flow.

In another application of this invention, the signal voltage and/or current is discretized, and the calculation result Mk+1is used to determine exceed or not the voltage or current in the transmission line specified threshold level.

In addition, the specified constant (MS) may be deducted from the calculation result Mk+1and the difference Mk+1, - MS can be impodimo be noted, this invention provides a relay protection means comparing the phase relations S1 and S2, as well as the energy content of the two total signals. No other known numerical method used in industrial research, has no ability to change their work depending on the energy content of the input signals S1 and S2. This characteristic is necessary in applications of relay protection, in which the working range is inversely proportional to the energy content. Other methods such as the method of Fourier filtering is widely used in industrial studies do not provide such an inverse relationship. The processing speed does not depend on the energy content of the input signals.

Thus, the input signals S1 and S2 digital comparator define the characteristics of the created device. Numerous applications of digital comparator below include relay protection, discussed above, and others.

BRIEF DESCRIPTION OF DRAWINGS

Fig. 1 schematically shows the input supply system for the application of relay protection and/or application of the digital comparator.

Fig. 2A schematically the dependence of the rotational torque from the angle between phases (between S1 and S2) of the cylindrical device.

Fig. 3A is a block diagram of a digital comparator in accordance with this invention. In this embodiment of the present invention calculates the Mk+1in real time, and Mk+1corresponds to the angular moment of the cylindrical device.

Fig. 3B shows a complex vector of characteristics of the digital comparator shown in Fig. 3A. Fig. 3B shows a complex vector of characteristics of the cylindrical device, shown in Fig. 2A, which are similar to the complex vector characteristics of the digital comparator and the output signal M

Fig. 4A shows a circuit that simulates the equations defining the input signals to the interface device determining the distance based on the digital comparator in accordance with this invention.

Fig. 4B is a block diagram of one embodiment of interface device determining the distance from the operator of the delay "d".

Fig. 4C shows a circuit that simulates the equations defining the input signals of the device determine the range of the values of the phase-to-ground on the basis of the digital comparator in accordance with this invention.

Fig. 4D pred accordance with this invention.

Fig. 5A shows the desired characteristic of the directional device in the R-X plane. Aiming devices listed in this description, have this characteristic.

Fig. 5B illustrates an idealized cylindrical device and the relation between M (torque) and (angle).

Fig. 5C - 5F show the processing performed directional devices with digital comparator in accordance with this invention.

Fig. 6A shows the symmetric components of the analog filter.

Fig. 6B and 6C schematically show options filter with symmetrical components in accordance with this invention. Fig. 6B shows a filter with symmetrical components Clarke. Fig. 6C shows a filter with symmetrical components and direct phase shift.

Fig. 7 schematically shows one variant of the device maximum current (at the entrance of which can serve as signals of voltage and current signals) and its implementation with the separation of the comparator in accordance with this invention. (Note that many devices on the basis of the digital comparator is used dividing the comparator, which is host of the solution

Fig. 8B schematically shows one version of the digital separation of the comparator in accordance with this invention.

Fig. 9 schematically shows the functional characteristic of the separation of the comparator.

Fig. 10 is an illustrative graph of the output signal of the dividing of the comparator.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE PRESENT INVENTION

A. OVERVIEW

Relay protection is a method of protecting electrical equipment, receiving the voltage or current from the system power supply. System relay protection requires certain input signals from the transmission line 10, which consists of three phase conductors A, B, C. Fig. 1 shows the standard way to obtain the required input signals. It is seen that the input voltage signals VA, VB, VC are obtained using a transformer voltages 12, and the input current signals IA, IB, IC are obtained using a current transformer 14. Values for the relay 16 are integrated voltages VA, VB, VC; the zero-sequence voltage - 3V0 = VA+VB+VC; complex currents IA, IB, IC; and the current zero-sequence - 3I0 = IA+IB+IC.

Century OF a device, used in a protective relay, to compare two complex vector of values for the phase and/or magnitude. A cylindrical device 18, schematically shown in Fig. 2A, is a well-known type comparator used in Electromechanical relays. Two distinctive characteristics of this cylindrical device is its insensitivity to the offset DC current and high speed.

When two signal voltages S1 and S2 are served on a cylindrical device 18, having density of streams B1 and B2. These density flows are characterized by a vector distribution on the surface of the rotating cylinder. If B1 and B2 are non-stationary, the cylinder excitatory currents, and these currents is proportional to the rate of change of B1 and B2 represented by the values dB1/dt and (dB2/dt, and angle theta (), which represents the phase difference between the signals S1 and S2. These currents cylinder is directed along the positive direction of Z-axis (i.e. perpendicular to the plane of Fig. 1). Using equation vector forces (see below), can be found field vector forces on the surface of the cylinder:

.

The interesting quantity is the torque about the axis Z. This PTO is as follows expressed through the density of streams B1 and B2:

< / BR>
,

where is the electrical conductivity (Cm/m)

= 3,1415,

r is the radius of the cylinder,

l is the length of the cylinder,

T - thickness of the cylinder.

If two time-dependent voltage signal S1(t) and S2(t) are served on a cylindrical device 18, is excited by a time varying flux density B(t). This flux density B(t) has components B1(t) and B2(t) associated with S1(t) and S2(t) by the following relations:

,

,

,

,

where N1 and N2 the number of turns of the input winding of the signals S1 and S2.

It should be noted that these equations do not contain any mechanism loss. These ratios include loss and can be used to determine S (input signal) with the values Century.

,

,

where LB and RB constants, determined to make the model more effective.

If the signals S1(t) and S2(t) is a sine wave such that:

S1(t) = Sin(t),

S2(t) = Sin(t),

then, torque (expressed in fractions of a unit) will equal:

M = 0 when = 0o,

M = -1 when = 90o,

M = 0, when = 180o,

M = 1 when = 270o,

as shown in Fig. 2B.

When applying the above adjusted the th form using the trapezoidal rule:

,

,

B1k= FK2[S1k+ S1k-1- FK1 B1k-1],

B2k= FK2[S2k+ S2k-1- FK1 B2k-1],

where:

,

< / BR>
and torque can be expressed in the following form:

Mk= B2k, B1k-1- B1k, B2k-1,

where k+1 is the current reference

k - previous reference

t is the sampling period.

Fig. 3A is a block diagram schematic of a digital comparator or system 20 to calculate the Mk. In the system of Fig. 3A "d" denotes a delay device; "" means summing device; "P" denotes a multiplier, and FK1 and FK2" refers to the amplifiers. The output signal Mksystem 20 represents a torque of Mkreal-time comparator, having a complex vector characteristics shown in Fig. 3B and illustrating the operational characteristics of the digital comparator 20. Taking the signal S1 for the reference level, the phase difference from 0 to -180omatch the working range of the device. The phase difference from 0oto +180omeets or outside the bounding range of the device.

This procedure can be used in the relay range, control relays, directed Auntie real-time two complex vector quantities. In special applications of the present invention, the mechanical influence, such as a force limiting spring, friction force and/or power offset can be taken into account in the model.

C. a DEVICE for DETERMINING the DISTANCE TO DETECT FAILURES

The procedure of implementation of the device determining the distance using a digital comparator is shown below.

Relay protection is associated with the detection of failures in the power supply devices. In relay protection transmission line is used relay range to detect several types of failures of the transmission line. These devices detect faults in transmission lines to a certain extent or range. In General, these devices measure the impedance, which is proportional to the distance from the relay location to the fault-location (hence the title "device for determining the distance"). Digital devices determine the range in accordance with this procedure detect failures faster known detectors failures, and in all other respects, has characteristics similar to Electromechanical devices for determining the distance. Digital methods, outlined below, are less susceptible to transients and noise, other than the working characteristics in the presence of transients.

1. THE INTERFACE DEVICE

Upon detection of interfacial failure digital input signals of the comparator are of the form:

S1 = VA - VB - (IA - IB)

S2 = VC - VB - (IC - IB).

The circuit shown in Fig. 4A, simulates these equations. Therefore, S1(t) and S2(t) can be obtained from phase-to-phase voltages and currents as follows:

,

.

If you convert these equations in discrete form and apply them to model a cylindrical device discussed above, you'll get:

< / BR>
< / BR>
which are the input signals of the digital comparator (also called the "generator torque"), derived earlier. S1kand S2kare then used to obtain B1kand B2kas specified above.

The above equations are the discrete implementation phase transfer device determining the distance that detects all types of failures in two phases, as well as some faults phase-to-phase-to-ground.

Fig. 4B is a block diagram of one implementation of the above equations in the case of a phase transfer device determining the distance. Note that the Delta currents Iab and Icb is discretized, delayed and combined with the delayed samples of the Delta on the th comparator 20, above. The output signal of the digital comparator is fed to a restrictive device, denoted by "MM" and included in the separation of the comparator 30 (see description below). The equations for B1 and B2 are solved and the cross-product B1kB2k+1and B1k+1B2kused to retrieve the member Mk. Amplifiers denoted by "AOO", "BOO", "CC", "EE", "FF", "FK1", "FK2" in accordance with their gains in the following list:

A00 = Rc+Lc/t

B00 = Lc/t

CC = t2/I

EE = I/(I+t2KC/I+tKD/I),

FF = 2+tKD/I

FK1 = (2LB-tRB)/t,

FK2 = t/(RB+2LB).

(Note that CC, EE and FF are to divider comparator).

2. A DEVICE THAT USES THE MAGNITUDE OF THE PHASE-TO-GROUND

The input signals are well known devices for detecting faults phase-to-earth look like:

S1 = VA-IA - K0I0)Zc,

S2 = VC-VB,

where ,

Zc = Rc+jXc = Rc+j2fLc,

.

In Fig. 4C presents a simplified diagram that models the above equation. If these equations are to be converted into discrete form and apply to the equations of the digital comparator, you'll get:

< / BR>
S2k= VckVbk,

which are the input signals of the digital comparator, the output value of the phase-to-ground, in accordance with this invention. Shows current and voltage is discretized and combined in adders, as shown, and then fed to the inputs of a digital comparator 20b. Members B1 and B2 then cross-multiplied, the result is the value of Mkand she served on the separation of the comparator 30 (see description below). Amplifiers denoted by "A01", "B01", "C01", "E01", "SS", "EE", "FF" in accordance with their gains in the following list:

A01 = Rc+Lc/t

B01 = Lc/t

C01 = (KrRc-KlXc)/3+(KrXc+KlRC)/3t,

E01 = (KrXc+KlRC)/3t,

CC = l/(l+t2KC/l+tKD/l),

EE = t2/l,

FF = 2+tKD/l.

Thus, the above General procedure of implementation of the device impedance measurement device to determine the distance). These devices have high performance because they require only three of the sampling period (k-1, k, k+1) to obtain a criterion of separation regardless of the sampling frequency. Moreover, other devices for determining the distance can be implemented in accordance with the procedure outlined here. The above devices determine the range studied, the device determining the distance and grounded device determining the distance (also called grounded Osttirol, used in relay protection to create a device definition range. The above procedure allows you to obtain any type of device definition range, currently used in industrial studies, to compare two complex vector quantities.

D. DIRECTIONAL DEVICE

Aiming devices are devices that are used in relay protection to determine the direction of power flow. Grounded aiming device on the basis of the digital comparator shown above are fast, making them ideal devices for application in relay protection and collaboration with the devices of determining the distance based on the digital comparator.

Fig. 5A illustrates the directional characteristics of such devices in the R-X plane. In this example, the forward direction corresponds to the power flow in the transmitting line. The reverse direction corresponds to the power flow of the transmission line.

Aiming devices are divided into two categories: phase directional device and grounded aimed device. Phase directional devices work in any conditions. Grounded is ewusie aiming devices:

1. DIRECTIONAL DEVICE WITH OFFSET NEGATIVE SEQUENCE

Using the output signals of the digital filter with symmetrical components, the following equations can be used to implement directional device with offset negative sequence:

B1k= FK2(V2k+ 2V2k-1+ V2k-2- FKl B1k-1)

B2k= FK2(I2k+ 2I2k-1+ I2k-2- FK1 B2k-1)

Mk= B2kB1k-1- B1kB2k-1.

In the above equations V2 and I2 are output signals of the digital filter with symmetrical components. This example is discussed below.

2. DIRECTIONAL DEVICE WITH OFFSET ZERO SEQUENCE

The following equations can be used to implement directional device with offset zero sequence:

B1k= FK2 (3V0k+ 23V0k-1+ 3V0k-2- FK1 B1k-1)

B2k= FK2 (AA 3I0k+ AB 3I0k-1+ BB 3I0k-2- FK1 B2k-1)

Mk= B2kB1k-1- B1kB2k-1,

where ,

,

AB = AA + BB.

In the above equations 3V0 = VA+VB+VC and 3I0 = IA+IB+IC.

3. GROUNDED DIRECTIONAL DEVICE CURRENT is aseminae directional device can be created by implementing the following equations:

,

B2k= FK2 (Ipolk+ 2Ipolk-1+ Ipolk-2- FK1B2k-1)

Mk= B1k-1B2k- B2k-1B1k.

4. PHASE DIRECTIONAL DEVICE

Phase directional device can be created by implementing the following equations:

B1k= FK2 (-VCBk- 2 VCBk-1- VCBk-2- FK1B1k-1)

B2k= FK2 (AA IAk+ AB IAk-1+ BB IAk-2- FK1 B2k-1)

Mk= B1k-1B2k- B2k-1B1k,

where ,

,

AB=AA+BB,

VCB - Delta-voltage (VC - VB).

Other directional devices can be implemented on the basis of the digital comparator above. The above equations define the "torque" of the device, which can be combined with digital dividing comparator.

Fig. 5C - 5F show the processing performed in the targeted devices.

Fig. 5C illustrates the flow of data in grounded directional device with offset negative sequence, which includes a digital comparator 20c and dividing the comparator 30. Input signals V2 and I2 digital comparator 20c are removed from the filter with symmetrical components. The solution ur of the unity of samples V2 and I2 for the education of the members B1 and B2 and then cross-multiply to obtain the member Mkserved on dividing the comparator 30. Amplifiers, denoted by "CC", "EE", "FF", "FK1 and FK2", you have the following gains:

CC = l/(l+t2KC/l+tKD/l),

EE = t2/l,

FF = 2+tKD/l,

FK1 = (2LB-tRB)/t,

FK2 = t/(tRB+2LB).

Fig. 5D illustrates the flow of data in grounded directional device with offset zero sequence. Members 3V0 and 3I0 obtained from real samples values of the system power supply (3V0 = VA+VB+VC and 3I0= IA+IB+IC). Solving equations grounded directional device with offset zero sequence involves combining samples 3V0 and 3I0 for education of the members B1 and B2, which are the input signals of the digital comparator 20d, and cross-multiplying the receiving member Mkserved on dividing the comparator 30. Amplifiers, denoted by "AA55", "BB55" and "AB55 have the following gains:

AA55 = 3/4-1/(4ft),

BB55 = 3/4-1/(4ft),

AB55 = AA55 + BB55.

Fig. 5E illustrates the flow of data in grounded directional device with a current offset, which includes a digital comparator 20e and dividing the comparator 30. Input 3I0 digital comparator is obtained from real samples values system electr point grounding system power supply. Solving equations grounded directional device with a current bias involves combining samples 3I0 and Ipolfor education of the members B1 and B2 and cross-multiply to obtain the member Mkserved on dividing the comparator.

Fig. 5F illustrates the data flow in the phase directional unit (phase A), which includes a digital comparator 20f and dividing the comparator 30. The input signal VCB digital comparator is equal to VC - VB, where VC and VB represent the real samples the voltage of phases a and B. IA is the integrated current of phase A. the Solution of equations of the phase directional device includes combining samples VCB and IA for the education of the members B1 and B2 and cross-multiply to obtain the member Mkserved on dividing the comparator. Amplifiers, denoted by "AA52", "BB52" and AB52 have the following gains:

AA52 = 1/4+3/(4ft),

BB52 = 1/4+3/(4ft),

AB52 = AA52 + BB52.

The above procedure is a standard procedure for directional devices. Specialists in this field understand that other directional devices can be implemented on the basis of the proposed invention.

That is, the FILTER SEE different parts of the supply system. The procedures below provide symmetrical components in the transient form. These procedures are aimed at high-speed devices and/or devices for determining the distance. Three such procedures below.

1. MODELING OF THE EXISTING ANALOG FILTER

Fig. 6A shows an analog filter. Components of positive and negative sequences in discrete form is given by the following equations:

< / BR>
where ,

< / BR>
where

.

Constants C1, R1, C2 and R2 can be carefully chosen to obtain the following optimized equations. There is a set of constants R1, C1, R2 and C2, which provides the minimum error and the correct phase shift.

2. DIRECT PHASE SHIFT

Equations symmetric component have the form:

,

.

These equations can be implemented using the phase-shifting identities:

,

.

Therefore, in discrete form, we get:

< / BR>
< / BR>
3. THE OUTPUT COMPONENT CLARK

By definition, components Clarke is:

I = 3I1+3I2 = 2Ia-Ib-Ic,

.

It follows that:

,

.

Using the operator

,

get:

,


Device maximum current below uses a digital algorithm that is fast and does not deteriorate when the DC offsets. It can be used as a level detector for voltage or current.

To implement odnorodnogo device maximum current one of the input signals of the digital comparator must be shifted in phase. Using this criterion, the following equations can be used to implement the device, the maximum current is not affected by the effects of DC offset. This device is ultra-fast.

B1K= FK2 (IAk+ IAk-1- FK1 B1k-1)

B2k= FK2 (IAk+ 2IAk-1+ IAk-2- FK1B2k-1)

Mk= B1k-1B2k- B2k-1B1k.

This output signal "torque" (Mk) may be submitted in digital dividing the comparator and opposite constant torque can be used to adjust the level of separation. In the above equations IA can be current, voltage or any other amount of power (such as for example, the symmetric component).

kcan be digital dividing the comparator 30, described below. Amplifiers "FK1 and FK2" have the following gains:

FK1 = (2LB-tRB)/t,

FK2 = t/(tRB+2LB),

RB = 1,0,

LB = 0,001.

G. SEPARATING COMPARATOR

The procedure below can be used to implement the digital device, the separation of the comparator delay. Digital dividing the comparator is included in all embodiments of the invention described above. Dividing the comparator is responsible for making decisions about the division. In other words, it decides when to perform the indication operation of the device to which it is connected.

Digital model of the moving contact cylindrical Electromechanical devices must simulate the Electromechanical characteristics of the cylindrical device. Digital comparator shown in Fig. 3A, was used to develop a digital dividing comparator (see pisanki rotational moment

MS - opposite spring (power) rotary moment,

MS - constant opposing torque,

l - moment of inertia of the cylinder.

Electromechanical equation for this model is:

.

Transforming the equation in discrete formkget:

,

where ,

,

.

In the case of digital dividing comparator subject to the following conditions:

If (Mk- MS) < 0, then the followingk/zero.

Ifk>tthen the following kequivalent totand partitioning is used.

Fig. 8B schematically shows one version of the digital separation of the comparator 30 in accordance with this invention. Input signal dividing comparator is the rotational moment Mk(generated by any of the above devices) and, as shown in Fig. 8B, a limited double inequality - MM < Mk< + MM, and then the opposite rotational moment of MS offset is subtracted from the Mk. Other schemes implement the above equations. Outputkthen compared withtto separate, as noted in condition 2. The ratios at which arator. This device generates a signal of logic "0" (false) if the device in an unusable state, and generates a signal of logic "1" (true) if the device is in working condition. The variable of "0" is input to the signal for the unit and is compared with the upper and lower limits. It should be noted that Fig. 10 shows a typical limits, however, may have selected a different limit values.

If the instantaneous value of the variable is "0" is greater than 0.6, in this case, a signal of logical "1" (true) logic relay protection device with microprocessor control. If this value is less than 0.6, then a logical "0" (false) is formed for logic relay protection device with microprocessor control. In this example, the limits of variation of the variable ranges from 0 to 1.

Specialists in this field understand that the present invention can be implemented in devices and methods that do not exactly match the above. Digital dividing the comparator is used in relay protection for execution in the digital code of the function(s) of the phase comparator. The cylindrical device in the Electromechanical relay is the main elements stored the military device, device maximum or minimum current, device maximum or minimum voltage, the control device, and in other special applications. A digital comparator is a phase comparator which can be used for the development of relay devices, such as those discussed above.

Development of the above algorithms digital comparator based on the analysis of a cylindrical device, but the equations have changed. They are not an exact model of the cylindrical device. In fact, the diversity of equations, constants, factors, ranges, etc. that are included in the equations implemented in the device with microprocessor control allows the designer more flexibility to adapt the operation of this device than a real cylindrical device.

1. How to compare two complex vector quantities in real time, each of which is represented by the signal S1(t) S2(t) and is determined by the magnitude and phase, which includes the receipt of reference (S1krepresenting the value of the first complex vector value in the first time, and receiving reference (S2krepresenting the second value to the value specified first complex vector value at the second time point, and obtaining reference (S2k+1representing the value of the specified second complex vector value in the same the second time point, wherein the gain derived quantities B1kB2k, B1k+1and B2k+1from S1kS1k+1, S2kS2k+1; multiply B1kB2k+1and B2kon B1k+1with receipt of the first works B1kX B2k+1and second compositions B2kX B1k+1outlines the first and the second works with receipts and scale the resulting sum to obtain the result of the calculation (Mk+1) corresponding to the phase difference, if any, between the first and the second complex vector value.

2. The method according to p. 1, wherein B1kand B2kare using the following ratios:

B1k= FK2 [S1k+ S1k-1- FK1 B1k-1]

B2k= FK2 [S2k+ S2k-1- FK1 B2k-1]

equations.

3. The method according to p. 2, characterized in that the FKI and FK2 are defined by the following relations

,

,

where RB and LB are constants.

4. The method according to p. 1, characterized in that S1kand S2kget discretization of transmitting signals do vary according to the sine law, or combination of voltages and currents.

6. The method according to p. 4, characterized in that the obtained calculation result Mk+1used to determine whether a failure in the transmission line.

7. The method according to p. 5, characterized in that the obtained result of the computation is used to detect interfacial failure in three-phase transmission line, and S1(t) and S2(t) are obtained from interfacial stresses and complex currents.

8. The method according to p. 6, characterized in that the result of calculation is used for failure detection phase and earth in the system of three-phase transmission line, and S1(t) and S2(t) is obtained from the voltage between phase and earth and complex currents.

9. The method according to p. 4, characterized in that the calculation result Mk+1used to determine the direction of power flow in the transmission line.

10. The method according to p. 4, characterized in that the calculation result Mk+1used to determine excess voltage or current in the transmission line specified threshold level.

11. The method according to p. 4, characterized in that it further carry out the subtraction of the specified constants (MS) from the received calculation result Mk+1and the difference Mk+1- MS is used for C is, trichosis the fact that the scaling operation involves multiplying the resulting amount by a specified factor proportional to the sampling period.

13. Device comparison in real-time two complex vector quantities, each of which is represented by the signal S1(t) S2(t) and is determined by the magnitude and phase containing a sampling means for obtaining reference (S1krepresenting the value of the first complex vector value in a first time, receiving a reference (S2krepresenting the value of the second complex vector value in the same first point in time of receipt of reference (S1k+1representing the value of the specified first complex vector magnitude for the second time, and obtain reference (S2k+1representing the value of the specified second complex vector value in the same the second time, characterized in that it introduced a means to obtain a derivative values B1kB2k, B1k+1and B2k+1from S1k, S1k+1, S2k, S2k+1; multiply B1kB2k+1and multiplying B2kon B1k+1to get the first piece B1kX B2k+1and second pieces is auchenia the result of the calculation (Mk+1) corresponding to the phase difference, if any, between the first and the second complex vector value.

14. The device according to p. 13, wherein B1kand B2kare using the following ratios:

B1k= FK2 [S1k+ S1k-1- FK1 B1k-1]

B2k= FK2 [S2k+ S2k-1- FK1 B2k-1]

where FK1 and FK2 are constants corresponding to the given equations.

15. The device according to p. 14, characterized in that FK1 and FK2 are defined by the following relations:

< / BR>
< / BR>
where RB and LB are constants.

16. The device according to p. 13, characterized in that S1kand S2kreceive sampling signals of the voltage or current in the transmission line.

17. The device according to p. 16, characterized in that the signals S1(t) and S2(t) represent the voltage or current varying in a sinusoidal manner, or combinations of voltages and currents.

18. The device according to p. 16, characterized in that it contains means for using the obtained result of the computation of Mk+1upon detection of a failure in the transmission line.

19. The device under item 18, characterized in that the result of the calculation used is mleczny currents.

20. The device under item 18, characterized in that the result of calculation is used for failure detection phase and earth in the system of three-phase transmission line, and S1(t) and S2(t) is obtained from the voltage between phase and earth and complex currents.

21. The device according to p. 16, characterized in that it further comprises means for using the obtained result of the computation of Mk+1to determine the direction of power flow in the transmission line.

22. The device according to p. 16, characterized in that it further comprises means for using the obtained result of the computation of Mk+1when determining excess voltage or current in the transmission line specified threshold level.

23. The device according to p. 16, characterized in that it further comprises means for subtracting a predetermined constant (MS) from the results of the computation of Mk+1and use the difference Mk+1- MS for receiving the signal (k+1), which defines the energy contained in the differential signal S1(t) S2(t).

24. The device according to p. 13, characterized in that it further comprises a means of scaling the received result of the calculation (Mk+1), multiplying the result by salanitri filter symmetric component, in which the output sequence component of the specified filter are input signals of the device.

 

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