RU2848701C1 - System for determining the parameters of an adaptive model of a synchronous generator in real time - Google Patents

Abstract

FIELD: electrical power engineering.

SUBSTANCE: invention can be used in operational dispatch and emergency control systems to determine the parameters of an adaptive model of a synchronous generator (SG) in real time based on measurements of instantaneous voltage and current values in alternating current power systems (ACPS) and the angular position of the rotor and/or the angular velocity of the SG rotor. The technical result is achieved by the fact that the system for determining the parameters of the adaptive model of the SG in real time in AC power systems contains a digital current and voltage recorder installed at a controlled point of the power system, a set of computing means and an output recorder. The computing complex contains a unit for calculating the parameters of the adaptive model of the SG in real time, and its output is connected to the input of the output recorder. The recorder displays the values of the calculated instantaneous parameters and has a digital interface for transmitting data to other systems for use in power system control tasks.

EFFECT: technical result of the invention is the determination in real time of the parameters of the adaptive model of the SG (SG load angle, inductive resistances along the longitudinal and transverse axes, resistances of the direct, reverse and zero sequences, Potier inductive resistance, electromagnetic torque, specific synchronising torque, moment of inertia of rotating masses, slip) for subsequent use in other systems (emergency automation, transient monitoring), as well as for further calculations of the static and dynamic characteristics of power system equipment.

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Description

Field of technology

The invention relates to the electric power industry and can be used in operational dispatch and emergency control systems for determining the parameters of synchronous machines and, in particular, synchronous generators (SG) in alternating current electric power systems (ACPS).

State of the art

For the study of dynamic processes in nonlinear systems (both in EPS in general and in SG in particular), the task of determining SG parameters in real time based on the results of measurements of SG operating mode parameters is relevant.

The parameters of the SG, determined during testing using methods established in the regulatory and technical documentation, correspond to the operating modes of the SG in which they are determined [1-3].

The electrical parameters of the SG change as the SG operating mode changes under operating conditions. The SG's technical condition affects its parameter values.

To determine the parameters of the SG, a simple structure SG model can be used, the parameters of which will be determined for the current operating mode of the SG (hereinafter referred to as the adaptive model) [4, 5].

Determining the parameters of the adaptive model of the SG during the electromechanical transient process will allow their values to be used in operational dispatch and emergency control systems to solve the problem of identifying deviations in the technical condition of the SG and planning measures to restore the technical condition of the SG.

Currently, the Unified Energy System of Russia operates a system for monitoring system regulators, which monitors the performance of automatic excitation control devices and excitation systems when managing EPS modes, based on the current recording of generator operating mode parameters in various operating modes - operational, emergency, special (minimum excitation limitation mode and double rotor current limitation mode) (RU 132637 Ul, H02J3/24, H02J 13/00, 20.09.2013).

Synchronized vector measurement devices (SVMD) are used to collect and primarily process information. The SVMD functions include performing, with standardized accuracy, measurements of synchronized current and voltage vectors (and other electrical parameters) at points in time that are clearly defined using global navigation satellite systems, and transmitting the measurement results to synchronized vector data concentrators [6].

Also known is a System for Determining the Synchronizing Power of a Synchronous Machine, which is taken as a prototype and is intended for determining the synchronizing power of synchronous machines in real time based on measurements of the electrical mode parameters and operating parameters of synchronous machines in AC power systems, including a digital recorder of electrical mode parameters and operating parameters of a synchronous machine, installed at a controlled point in the power system; a set of computing means and an output recorder containing a human-machine interface (RU 2564539 CI, H02J3/24, 01.10.2014).

The essence of the invention

The technical result of the invention is the determination in real time, based on the data of current and voltage measurements at a controlled point of the EPS, of the parameters of the adaptive model of the SG (SG load angle, inductive resistances along the longitudinal axis and along the transverse axis, resistances of direct, negative and zero sequence, Potier inductive resistance, electromagnetic torque, specific synchronizing torque, moment of inertia of rotating masses, slip) for their subsequent use in other systems (emergency control systems, transient mode monitoring systems - TMMS), as well as for further calculations of the static and dynamic characteristics of the EPS equipment.

The specified technical result is achieved by the fact that the system for determining instantaneous values of the parameters of the adaptive model of the SG, like the prototype, contains the following connected in series:

- a digital recorder of electrical mode parameters and SG operating mode parameters, which records the measured SG operating parameters (voltage and current at the terminals of the SG armature winding, voltage and current of the excitation winding, SG rotor position angle), and generates vectors of synchronized vector measurements of SG operating mode parameters;

- a set of computing tools, including a unit for monitoring the composition of measurements received from a digital recorder of electrical mode parameters and operating mode parameters of the SG, a unit for storing SG parameters and characteristics, a calculation unit (a unit for calculating synchronizing power in the prototype);

- an output recorder containing a human-machine interface displaying the values of the calculated parameters. Unlike the prototype, the digital recorder of electrical mode parameters and SG operating mode parameters additionally records the rotational speed or angular velocity of the SG rotor and generates vectors of electrical mode parameters and SG operating parameters with the sampling frequency of the analog-to-digital converter (ADC). A block for calculating the parameters of the SG adaptive model is used as a calculation unit. In this unit, the values of the following parameters of the SG adaptive model are calculated based on the measurements of the electrical mode parameters and SG operating mode parameters performed by the digital recorder: synchronous machine load angle, inductive reactances along the longitudinal axis and along the transverse axis, positive, negative, and zero-sequence resistances, Potier inductive reactance, electromagnetic torque, specific synchronizing torque, moment of inertia of rotating masses, and slip.

The output recorder additionally contains a digital interface for transmitting data to other systems for use in power system control tasks.

The proposed system for determining the parameters of the adaptive SG model uses synchronized vector measurement technology, which results in voltages and currents being represented as vectors in a coordinate system rotating at a speed corresponding to the alternating current frequency. This technology is also used, in particular, in SMPR devices.

Brief description of the drawings

The block diagram of the system for real-time determination of the parameters of the adaptive model of the SG is shown in the figure. The proposed system includes:

- digital recorder 1 of electrical mode parameters and SG operating mode parameters;

- a set of computing tools, including:

• block 2 for monitoring the composition of measurements received from the digital recorder of electrical mode parameters and operating mode parameters of the SG,

• block 3 for storing parameters and characteristics of the SG,

• block 4 for calculating the parameters of the adaptive model of the SG;

- output recorder 5 with human-machine and digital interfaces.

Implementation of the invention

The measured values include electrical parameters measured by the measuring instrument in accordance with the requirements of the standard [6], signals of the angular position of the rotor and/or the rotation frequency or angular speed of the rotor of the SG.

The inputs of digital recorder 1 receive signals of the corresponding parameters from standard current sensors (CT) and voltage sensors (VT) of each of the three phases at the controlled point of the EPS (the point of connection of the SG to the station busbars), voltage and current of the excitation winding (F), sensors of the angular position of the rotor (Ang) and/or the rotation frequency or angular speed of the rotor of the SG (N).

These parameters are digitalized and discrete signals are generated at the output of digital recorder 1, with the sampling frequency (the frequency of taking samples of the measured signals) of the analog-to-digital converter (ADC).

The received signals are fed to the input of block 2, where the presence of measurements required for calculating the parameters of the adaptive model of the SG in block 4 is determined.

The input of block 2 is connected to the output of digital recorder 1.

Block 2 has two outputs.

The output marked "D" is activated if all measurements necessary for calculating the parameters of the adaptive model of the SG are available:

- vectors of electrical voltages and currents of the armature winding phases;

- angular position of the rotor (Ang);

- angular velocity of rotation of the stator field;

- angular velocity of rotation of the SG rotor.

The output marked "H" is activated in the event of the absence of any of the measurements required to calculate the parameters of the adaptive model of the SG.

Output "D" of block 2 is connected to the input of block 4. Output "D" is supplied with measurement data required for calculating the parameters of the adaptive model of the SG.

Output "H" of block 2 is connected to the input of block 3. Output "H" is fed with data from existing measurements and information about missing measurements required to calculate the parameters of the adaptive model of the SG.

Block 3 stores the design and/or experimental parameters and characteristics of the SG:

- number of pole pairs;

- rated values of electrical voltages and currents of the armature winding and excitation winding;

- active resistance of windings;

- winding data of the windings;

- idle speed characteristic;

- characteristic of 3-phase short circuit;

- inductive load characteristic. The output of block 3 is connected to the input of block 4.

Block 4 calculates the parameters of the adaptive SG model. Block 4's operation is based on the solutions of the following equations:

- equation of rotor motion [4]:

where J is the moment of inertia of the rotor [kg-m];

- the first derivative of the angular velocity of rotation of the rotor Ω with respect to time t;

T - time [s];

Ω - angular velocity of rotor rotation [rad/s];

- the first derivative of the moment of inertia of the rotor J with respect to the magnitude of the rotor rotation angle γ;

γ - angle of position (rotation) of the rotor [rad];

М _Т – mechanical torque of turbine [N-m];

M _SG - mechanical moment SG [N-m].

For the case when it is assumed that J=const, the derivative the equation of motion for the SG rotor is simplified:

- Park-Gorev equations for the dynamic mode and static mode [7, 8]:

Where

ψ _d =L _d ⋅i _d +L _ad ⋅i _f +L _ad ⋅i _kd ;

ψ _q =L _q ⋅i _q +L _aq ⋅i _kq ,

ψ _f =L _ad ⋅i _d +(L _ad +L _fσ )⋅i _f +L _ad -i _kd ;

ψ _кd =L _ad ⋅i _d +L _ad ⋅i _f +(L _ad +L _Kdσ )⋅i _Kd ;

ψ _кq ⁼ L _aq ⋅i _q +(L _aq +L _Kqa )⋅i _кq

u _d , u _q , i _d , ψ _d , ψ _q - components of voltage, current, and flux linkage along the d and q axes, respectively;

R - active resistance of the armature winding phase;

γ - angle of position (rotation) of the rotor;

u _f , i _f , ψ _f , R _f - voltage, current, flux linkage and active resistance of the reduced excitation winding along the d-axis;

u _kd , u _kq , i _kd ,i _kq , ψ _kd , ψ _Kq , R _Kd , R _Kq - voltage, current, flux linkage and active resistance of the reduced damper winding along the d and q axes, respectively;

L _d , L _q - total inductances of the armature along the longitudinal and transverse axes;

L _ad , L _aq - main inductances of the armature along the longitudinal and transverse axes;

L _fσ is the leakage inductance of the reduced excitation winding;

L _Kdσ , L _Kqσ - leakage inductances of the reduced damper winding along the longitudinal and transverse axes;

- a simplified equation of electrical voltage equilibrium for static conditions [7, 8]:

Where - the vector of excitation EMF induced in the armature winding phase by the mutual induction field from the excitation MMF;

Ů - voltage vector at the terminals of the armature winding;

İ, İ d, İq - current vector, components of the current vector along the longitudinal axis and along the transverse axis, respectively;

R - active resistance of the armature winding phase;

Хр - Potier inductive resistance or nominal value (calculated or determined experimentally) of the inductive resistance of the armature winding;

Xad is the synchronous inductive resistance of the armature reaction along the longitudinal axis;

Xaq is the synchronous inductive resistance of the armature reaction along the transverse axis;

Xd - synchronous inductive resistance along the longitudinal axis;

Xq - synchronous inductive reactance along the transverse axis;

- equilibrium equation of magnetomotive force [3, 7, 8]:

Where - the resulting vector of the magnetomotive force;

- vector of magnetomotive force of the excitation winding of the SG;

- the excitation vector of the equivalent magnetomotive force of the armature winding of the SG Fam;

- equations of electromagnetic moment and specific synchronizing moment, resistance of direct, reverse and zero sequence of the method of symmetric components for the analysis of asymmetric modes [7, 8].

The system allows calculating instantaneous values of parameters in operational static and dynamic modes of the SG.

The calculated parameters of the adaptive model of the SG have the sampling frequency of the analog-to-digital converter (ADC). Unit 4 operates in real time, as confirmed by experimental results.

The algorithm for calculating instantaneous values of the parameters of the adaptive model of the SG includes the following steps:

- calculation of the load angle of a synchronous machine;

- determination of inductive resistance values:

• calculation of inductive resistance of Potier SG;

• calculation of inductive resistance accordingly:

in steady state - X _q , X _d ,

in the super-transient mode - Xq", Xd",

in transition mode - Xq', Xd';

- determination of the components of the direct, reverse, and zero sequence vectors for electrical voltages and electric current of the SG stator winding;

- calculation of resistances of direct, reverse, zero sequence;

- calculation of electromagnetic power and electromagnetic moment of the SG;

- calculation of turbine torque in steady-state mode or for a small time interval of dynamic mode;

- calculation of the equivalent moment of inertia of the SG rotor and turbine from the equation of rotor motion;

- calculation of the specific synchronizing power and specific synchronizing torque of the SG [7, 8].

The values of the calculated instantaneous parameters of the adaptive model of the SG are fed to the input of block 5 - the output recorder, which contains the human-machine interface and communication interfaces with adjacent systems.

The calculated values of the parameters of the adaptive model of the SG can be used to solve problems of operational dispatch control of the EPS, problems of emergency control and problems of determining the characteristics of the EPS and its individual elements, to solve the problem of identifying deviations in the technical condition of synchronous generators and planning measures to restore their technical condition in operational dispatch and emergency control systems.

In particular, the values of instantaneous parameters of the SG can be used in calculating the static and dynamic characteristics of elements and parts of the EPS, etc.

The correctness of the results of determining the parameters of the adaptive model of the SG in the operational modes of the SG in real time is determined by the use of classical equations of the SG [7,8]. The performance of the proposed technical solution is confirmed by test results.

The implementation of the proposed technical solution can be carried out using modern digital means of signal processing and calculation.

Multifunctional measuring transducers used in SMPR systems, which enable synchronized vector measurements, can be used as digital recorders of electrical mode parameters. The AS SI SMPR (automated data collection system SMPR) terminal can be used as an output recorder containing a human-machine interface. Thus, the system for determining instantaneous values of electrical mode parameters can be integrated into the SMPR.

Sources of information

1. GOST 10169-77. Three-phase synchronous electric machines. Test methods. Replaces GOST 10169-68; introduced on 01.01.1978 in terms of paragraphs 25-27 on 01.07.1979. Moscow: Publishing House of Standards, 1984.

2. GOST R IEC 60034-4-2012. Rotating electrical machines. Part 4. Methods for experimental determination of parameters of synchronous machines. Introduced on June 1, 2014.

3. Zherve G.K. Industrial testing of electrical machines. 4th ed., abridged and revised. L.: Energoatomizdat. Leningrad branch, 1984. 408 p.

4. Adaptive model of a synchronous machine with parameters determined in operating modes / Berdin A.S., Gerasimov A.S., Kovalenko P.Yu., Moiseichenkov A.N., Senyuk M.D. // Bulletin of the Scientific and Technical Center of the Unified Energy System. 2020. No. 2 (83). P. 74-84.

5. Comparison of methods for determining the synchronizing power of a synchronous machine based on the results of experimental studies on an electrodynamic model / Berdin A.S., Gerasimov A.S., Kovalenko P.Yu., Moiseychenkov A.N. // Bulletin of the Scientific and Technical Center of the Unified Energy System. 2015. No. 2 (73). P. 72-82.

6. GOST R 59365-2021. Unified Energy System and Isolated Energy Systems. Relay Protection and Automation. Transient Monitoring System. Synchronized Phasor Measurement Devices. Standards and Requirements. Applicable from May 1, 2021.

7. Vol'dek A.I. Electrical machines. 3rd ed., revised. L.: Energia, 1978. 832 p.

8. Ivanov-Smolensky A.V. Electrical machines: a textbook for university students studying in the direction of training graduate specialists in "Electrical engineering, electromechanics and electrical technology": in 2 volumes / A.V. Ivanov-Smolensky. 2nd ed., revised and enlarged. Moscow: MPEI Publishing House, 2004.

Claims (1)

A system for determining in real time the parameters of an adaptive model of a synchronous generator, comprising a digital recorder of the electrical mode parameters and the operating mode parameters of the synchronous generator, a set of computing means including a unit for monitoring the composition of measurements received from the digital recorder of the electrical mode parameters and the operating mode parameters of the synchronous generator, a unit for storing the parameters and characteristics of the synchronous generator and a calculation unit, and an output recorder containing a human-machine interface, characterized in that the digital recorder of the electrical mode parameters and the operating mode parameters of the synchronous generator additionally records the rotation frequency or angular velocity of the rotor of the synchronous generator; forms vectors of the electrical mode parameters and the operating parameters of the synchronous generator with the frequency of the analog-to-digital converter of the synchronized vector measurement device; the computing complex includes a unit for calculating the parameters of the adaptive model of the synchronous generator, which calculates the following values: the load angle of the synchronous machine, the inductive resistances along the longitudinal axis and along the transverse axis, the resistances of the direct, negative and zero sequences, the Potier inductive resistance, the electromagnetic torque, the specific synchronizing torque, the moment of inertia of the rotating masses, and slip; - wherein the discrete signals from the digital recorder of the electrical mode parameters and the operating mode parameters of the synchronous generator are fed to the input of the unit for monitoring the composition of measurements of the digital recorder of the electrical mode parameters and the operating mode parameters of the synchronous generator, the first output of which is connected to the unit for storing the parameters and characteristics of the synchronous generator, and the second output of the unit for monitoring the composition of measurements of the digital recorder of the electrical mode parameters and the operating mode parameters of the synchronous generator and the output of the unit for storing the parameters and characteristics of the synchronous generator are connected to the input of the unit for calculating the parameters of the adaptive model of the synchronous generator, which feeds the values of the calculated parameters to the output recorder containing a human-machine interface, which is supplemented by a digital interface for transmitting data to other systems.