# The filter is symmetrical components of the electrical signal

The invention relates to measurement devices, and more specifically to devices designed to highlight the components of the negative sequence voltage, and can be used in the composition of measurement devices, protection and alarm systems three-phase alternating current systems. The technical result consists in obtaining the full spectrum of the symmetric components of the electric signal at high speed and the accuracy of the measurement signal in the transient operation modes. The filter is symmetrical components of the electric signal terminal phase And the monitored signal is connected to the first input of the first adder, the clamp phase connected through inverting input of the first block of differentiation with the second input of the first adder, and after inverting input of the first proportional block with the third input of the first adder. The clamp phase connected through a non-inverting input of the second block of differentiation with the fourth input of the first adder, and after inverting input of the second proportional block with the fifth input of the first adder, the output of which through the non-inverting input of the third proportional block associated with the first output device. It contains the third is aim phase And is additionally connected to the first input of the second adder and the first input of the third adder. The clamp phase additionally connected to the second input of the second adder, the second input of the third adder is connected via a non-inverting input of the third block of differentiation, and with the third input of the third adder - via inverting input of the first proportional block. The output of the second adder through a non-inverting input of the fourth proportional block associated with the second output device, the terminal phase With additionally connected to the third input of the second adder, with the fourth input of the third adder is connected across the inverting input of the fourth block of differentiation, and with the fifth input of the third adder - via inverting input of the second proportional block, and the output of the third adder through a non-inverting input of the fifth proportional block associated with the third output device. When the device is in non-stationary mode, the first output component is formed of an electrical signal back to the zero sequence, the second output - zero sequence, the third output is a direct zero-sequence. 1 Il. The invention relates to measurement devices, and more specifically to devices intended the TV measurement protection and alarm systems three-phase alternating current systems.Known measuring transducer symmetric components of the electrical quantities (see ed. mon. The USSR 1432425 on CL IPC

^{7}G 01 R 29/16), containing the first phase-shifting element and an adder whose output is the output of the measuring transducer, the second and third phase shifting elements and four scaling (or proportional) block, and the input of each phase shifting element connected respectively to the terminal phase of the input electric quantity, the outputs of the first phase shifting element directly, and the second and third through the first and second scaling (proportional to) the blocks are connected to the inputs of the adder, the inputs of the second and third phase shifting elements combined with inputs respectively of the third and fourth scaling (proportional) blocks, the outputs are connected to the fourth and fifth inputs of the adder.This device has a high accuracy when the frequency deviation of the monitored signal, but its performance is limited by the presence of inertial elements. In addition, the device prototype primary signal is converted not only on the Mach can lead to additional measurement error.Known filter voltage reverse order (see RF patent 2159939 on CL IPC

^{7}G 01 R 29/16) closest to the claimed technical solution and adopted as a prototype, in which the terminal phase And connected to the first input of the adder, the clamp phase connected through inverting input of the first block of differentiation with the second input of the adder, and after inverting input of the first proportional block with the third input of the adder, the clamp phase connected through a non-inverting input of the second block of differentiation with the fourth input of the adder, and after inverting input of the second proportional block with the fifth input of the adder, the output of which is connected to the input of the third proportional block so the output of the third proportional block is the output device.This filter, with its high performance and measurement accuracy, is able to allocate only the electrical signal reverse order, which limits its use in the devices of relay protection and automatics.The present invention allows to obtain a complete range of symmetrical components of the electric signal at high speed and the accuracy of the measurement signals are the different components of an electrical signal, in which the terminal phase And the monitored signal is connected to the first input of the first adder, the clamp phase connected through inverting input of the first block of differentiation with the second input of the first adder, and after inverting input of the first proportional block with the third input of the first adder, the clamp phase connected through a non-inverting input of the second block of differentiation with the fourth input of the first adder, and after inverting input of the second proportional block with the fifth input of the first adder, the output of which through the non-inverting input of the third proportional block associated with the first access device further comprises third and fourth blocks differentiation, the second and third adders and the fourth and fifth proportional blocks, and terminal phase And is additionally connected to the first input of the second adder and to the first input of the third adder, the clamp phase additionally connected to the second input of the second adder, the second input of the third adder is connected via a non-inverting input of the third block of differentiation, and with the third input of the third adder - via inverting input of the first proportional block, and the output of the second summatory With additionally connected to the third input of the second adder, with the fourth input of the third adder is connected across the inverting input of the fourth block of differentiation, and with the fifth input of the third adder - via inverting input of the second proportional block, and the output of the third adder through a non-inverting input of the fifth proportional block associated with the third output device.When the device is in non-stationary mode, the first output component is formed of an electrical signal reverse sequence, the second output - zero sequence, the third output - direct sequence.All elements of the proposed device can be implemented on instantaneous elements, which ensures its high performance under all possible operating modes. The selection of the full range of symmetrical components of an electrical signal without converting the phase of the primary signal, in turn, significantly increases the functionality of the filter at high precision.The drawing shows a block diagram of the filter is symmetrical components of the electrical signal.The filter contains the first 1 and second 2 proportional blocks, the first 3, the third 4, the second 5 and the fourth 6 blocks trim is proportional to the blocks.The terminal phase And the monitored signal is connected to the first input of the first adder 7, the first input of the second adder 8 and the first input of the third adder 9.The clamp phase is connected to the second input of the second adder 8 directly to the second input of the first adder 7 is connected across the inverting input of the first block of differentiation 3, and with the second input of the third adder 9 is connected via a non-inverting input of the third block of differentiation 4. With the third input of the first adder 7 and the third input of the third adder 9 clamp phase connected through inverting input of the first proportional block 1.The clamp phase is connected to the third input of the second adder 8 directly, with the fourth input of the first adder 7 is connected through a non-inverting input of the second block of differentiation 5, and the fourth input of the third adder 9 is connected across the inverting input of the fourth block of differentiation 6. With the fifth input of the first adder 7 and the fifth input of the third adder 9 clamp phase connected through inverting input of the second proportional block 2.The output of the adder 7 is connected with reinvestiruet the entrance to the third proportional block 10, the output of which is the first wyhoon block 11, the output is the second output of the device in question.The output of the adder 9 is connected to reinvestiruet entrance of the fifth proportional block 12, the output of which is the third release of the device in question Blocks 1-6 and 10-12 can be implemented using operational amplifiers. The gain is proportional to units 1, 2, 10-12 is determined by the ratio of the resistances at the input of the amplifier and the feedback circuit. Blocks differentiation 3-6 at the entrance contain a capacitor and feedback resistor.The action of the device is based on the use of the method of symmetrical components. Let be a system of phases a, b and C, with clamps which are removed electrical signalsaccordingly, the values of which can be identified by the expressionwhere U

_{and}U

_{b}and U

_{with}- the amplitude values of the signals of the phases a, b and C;angular frequency of the signal,= 2f; f is the signal frequency;

_{1}- the angle at which a signalahead signal

_{2}- polii with the specified method the expression for the component of the direct sequencean electrical signal phase And is

where a is the operator of the three-phase system;

e=2,71828... .The expression for the component of the return sequencean electrical signal phase And is

The expression for the component of the zero sequencean electrical signal phase And is

Multiply the vector phase to three-phase system operators. Using the formula of the trigonometric sine decomposition of two angles, we get

A similar calculation was performed for phase:

Express in expressions (5) - (8) second components through derivative signalsrespectively

Substituting formula (9), (10) in expression (5) to (8), we obtain

where K

_{12}=was 2.7610

^{-3}C.We will substitute the expressions (11), (14) in expression (2) and expression (12), (13) in expression (3), the result will be

where K

_{3}=1/3.From expressions (15) and (16) it follows that for signal receiving direct or reverse order of one phase (e.g., phase A), must submit to the appropriate adder signal of this phase, scaled inverted signals of the other two phases (the scaling factor K

_{1}=0.5), the non-inverted scaled signal is the derivative of the signal phase and scaled inverted signal of the derivative of the signal phase for direct sequence, scaled inverted signal of the derivative of the signal phase and non-inverted scaled signal derived signal is phase - reversed sequence (at frequency voltage 50 Hz scale factor

_{2}=was 2.7610

^{-3}C). To obtain the zero-sequence signal enough to put in the appropriate adder signals of all three phases according to the expression (4).In order to distinguish the signal direct, reverse or zero multiply by the scaling factor K

_{3}=1/3.The device operates as follows.The controlled signal is taken from the terminals of the phases a, b and C. the Signal u

_{and}with clamp phase And goes directly to the first input of the first adder 7, the first input of the second adder 8 and the first input of the third adder 9. The signal u

_{b}with clamp phase In forks to the inverting input of the first block of differentiation 3, at the non-inverting input of the third block of differentiation 4, to the inverting input of the first proportional block 1 and to the second input of the second adder 8.In the first block of differentiation 3 signal u

_{b}is inverted, is differentiated and multiplied by the scaling factor K

_{2}. At the output of block 3 is formed by the signal-To

_{2}u

_{b}that is supplied to the second input of the first adder 7.In the third block of differentiation 4 signal u

_{b}differentiated and multiplied by the scaling factor K

_{2}. At the output of block 4 is formed by the signal +K

_{2}u

_{b}that is supplied to the second input of the third adder 9.In proportional block 1 signal phase u

_{b}inverted and scaled. The resulting signal-To

_{1}u

_{b}from the output of the block 1 is supplied to the third is to a non-inverting input of the second block of differentiation 5, to the inverting input of the fourth block of differentiation 6, to the inverting input of the second proportional block 2 and the third input of the second adder 8.In the second block of differentiation 3 signal u

_{c}differentiated and multiplied by the scaling factor K

_{2}. At the output unit 5, a signal is generated +K

_{2}u

_{c}which is supplied to the fourth input of the first adder 7.In the fourth block of differentiation 6 signal u

_{c}is inverted, is differentiated and multiplied by the scaling factor K

_{2}. At the output of block 6, a signal is generated To

_{2}u

_{c}that comes to the fourth input of the third adder 9.In proportional block 2 signal phase u

_{c}inverted and scaled. The resulting signal-To

_{1}u

_{c}from the output unit 2 is supplied to the fifth input of the first adder 7 and the fifth input of the third adder 9.In the result of summation of the input signals at the output of the first adder 7 is formed a signal equal to three times the signal value of the negative sequence phase a, i.e. 3u

_{A2}that comes to the non-inverting input of the third proportional block 10, where it is multiplied by a factor K

_{3}. That is Mirovaya input signals at the output of the second adder 8, a signal is generated, equal to three times the value of the signal zero-sequence phase a, i.e. 3u

_{A0}that comes to the non-inverting input of the fourth proportional block 11, which is multiplied by a factor K

_{3}. Thus, the output of block 11, a signal is generated zero sequence u

_{A0}.In the result of summation of the input signals at the output of the third adder 9 is formed a signal equal to three times the value of the signal direct sequence phase a, i.e. 3u

_{A1}that comes to the non-inverting input of the fifth proportional block 12, where it is multiplied by a factor K

_{3}. Thus, the output of block 12 is formed the signal direct sequence u

_{A1}.The proposed device by introducing the third and fourth blocks differentiation, second and third adders, fourth and fifth proportional blocks, while the terminal phase And is additionally connected to the first input of the second adder and to the first input of the third adder, the clamp phase additionally connected to the second input of the second adder, the second input of the third adder is connected via a non-inverting input of the third block of differentiation, and with the third input and the third is C non-inverting input of the fourth proportional block associated with the second output device, terminal phase With additionally connected to the third input of the second adder, with the fourth input of the third adder is connected across the inverting input of the fourth block of differentiation, and with the fifth input of the third adder - via inverting input of the second proportional block, and the output of the third adder through a non-inverting input of the fifth proportional block associated with the third output of the device, while maintaining the high performance and accuracy of measurement of an electrical signal in the transient operation modes, simultaneously with the component reverse order to obtain the components of the forward and reverse sequences, which significantly extends the functionality of the device.

Claims

**Same patents:**

FIELD: electric engineering.

SUBSTANCE: method includes estimation of quality coefficients of electric energy in electric energy system, determining degree of matching of these coefficients to normal values, forming of control signal for correcting devices and predicting electric energy characteristics expected after effect of these devices. On basis of analysis of predicted characteristics quality coefficients are newly estimated and if necessary control signals for correction devices are formed. Estimation of not only voltage and frequency is provided, but also current. Whole cycle is repeated for each node of electric energy system.

EFFECT: higher efficiency.

1 dwg

**FIELD: electrical and power engineering.**

**SUBSTANCE: proposed method intended for measuring current and voltage unbalance level and organizing on-line impact on them in three-phase power systems characterized in low quality of their power characteristics includes measurement of unbalance level with respect to reverse and zero sequence of both line and phase voltages and currents at frequency of each harmonic component. Frequency at which unbalance in analyzed characteristics occurs is found. Results obtained are used to generate control signal by correcting devices.**

**EFFECT: facilitated procedure.**

**1 cl, 5 dwg**

FIELD: test equipment.

SUBSTANCE: device has several units for conducting signal preliminary processing connected in parallel to final data processing unit through communication line. Device also has signaling unit. Final data processing unit has operator's PC and data collecting unit made on the base of industrial computer. Preliminary data processing unit has units for connecting object to measuring terminals of phases, commutation unit, a alarm protection unit and measuring unit. The latter has analog signal preliminary processing unit provided with primary converters on the base of precision resistors, analog signal basic processing unit, digitization unit and communication interface. Device performs continuous centralized inspection of capacitor-type paper-oil equipment (high-voltage terminals, current transformers) to detect leakage in insulators at early stage without switching equipment off.

EFFECT: improved reliability of operation.

4 cl, 7 dwg

FIELD: transformation equipment engineering, possible use for engineering indicators of three-phased voltage.

SUBSTANCE: device contains three-phased bridge rectifier, made on diodes (1-6). Output contacts of rectifier, being output contacts of indicator, are meant for connecting load circuit (7). Resistors (8-10) are introduced into input circuits of alternating current, connected to corresponding phases of voltage supply being measured. Resistance value of each resistor (8-10) equals to (0,5÷0,7) of value of active resistance of constant current load chain (7).

EFFECT: increased precision of measurements due to improved dynamic characteristics of measuring device.

2 dwg

FIELD: electric power engineering, possible use in electric supply systems for determining reverse series voltage.

SUBSTANCE: reverse series voltage filter contains symmetric precision resistive-capacitive circuit of "triangle", sides of which contain resistors and capacitors. Middle points between resistors constitute three-phased inputs of bridge rectifier loaded on measuring volt meter of magneto-electric system. Shoulder parameters are selected to suppress direct series voltage at the input of three-phased bridge rectifier, making it possible to single out voltage of reverse series, value of which is proportional to rectified bridge voltage. In the same middle points, capacitors are included, connected according to "star" circuit, to prevent influence of highest harmonic components.

EFFECT: increased reliability and increased stability of filter under influence of harmonic voltage components.

3 dwg

FIELD: physics.

SUBSTANCE: method involves measurement of instant phase voltage readings arrays in asymmetrical phase load mode and of symmetrical signal component of phase A obtained in differential amplifier by combining phase A u_{AO1}(t_{j}) signal and composite signal of three phases from resistor Y-point obtained at the same moments of time t_{j}=t_{1}, t_{2}, ..., t_{N} with increment where T is current (voltage) signal period and N is the number of readings per period; simultaneously asymmetrical U_{AO1} and symmetrical U_{A} signal components of phase A are defined. Reactive quasipower of phase A voltages is defined, current signal readings are multiplied together, their active quasipower at phase A voltages is defined. Sine and cosine of vector divergence angle F between voltages U_{A} and U_{AO1 }are defined. U_{N} neutral voltage is determined. Sine of vector divergence angle D between voltages U_{AO1} and U_{N} and sine of vector divergence angle E between voltages U_{A} and U_{N} are defined.

EFFECT: improved precision and simplicity of calculation.

3 dwg, 2 tbl

FIELD: electricity.

SUBSTANCE: proposed filter has input terminals (1), (2), (3) for connecting to a full-wave rectifier (4) of a three-phase voltage system and a precision resistive-capacitive filter circuit of the sixth and the rest of even harmonics, which has a resistor (5) and capacitors (6), (7). At the output of the filter, there is a bridge circuit, the branches of which are resistors (8), (11), diodes (9), (12) and moving-coil voltmeter (10), connected in the diagonal of the bridge. The negative voltage sequence corresponds to the second harmonic of the output voltage of the rectifier (4), which is let pass by the precision resistive-capacitive circuit with elements (5), (6), (7) and which blocks the sixth and the following even harmonics. The proposed circuit for determining negative sequence voltage is not susceptible to effect of higher harmonics of the mains voltage.

EFFECT: increased reliability and immunity of the negative sequence voltage filter to effect of voltage harmonic components.

5 dwg

FIELD: electricity.

SUBSTANCE: device comprises a negative sequence voltage filter, which represents a resistor-capacitor circuit, connected to the first, second and third input terminals, and also to the first and second output terminals of this filter, to which a load of the specified measuring converter is also connected, at the same time between the first input and the first output terminals of this filter there is the first capacitor connected, between the first output and the second input terminals of the filter there is the first resistor, between the second input and the second output terminals of the filter there is the second capacitor, and between the second output and the third input terminals there is the second resistor, besides, at the rated value of frequency of a three-phase circuit, to which the specified measuring converter is connected, and whenever the load is disconnected from the output terminals of the filter, the current of a section in the resistor-capacitor circuit connected between the first and second input terminals of the filter advances a sinusoidal electromotive force of a source connected between these terminals by π/6.

EFFECT: improved selectivity and device simplification.

3 dwg