Application of unified microprocessor relay protection units in electrical machine diagnostics

The article concentrates on the topical issue connected with the detection of defects in the rotor winding of electric machines. The experimental sampling and digital processing of electrical signals from controlled windings is in the basis. The authors conducted the research using two experimental units for asynchronous motor and synchronous generator, respectively. A distinctive feature of the proposed research stands is in solving the problems of digital processing and data analysis on the basis of the application of microprocessor relay protection unit BMRZ developed in Russia. The authors applied method of wavelet decomposition to select the detailing component. They also presented the results of experiments for the breakage in the short-circuit rotor of an asynchronous motor and proved that the microprocessor-based BMRZ device is capable of digitizing at a sampling rate that meets the requirements, and in conjunction with the data processing algorithms that carry out the selective determination of hard-to-detect defects, is applicable in the diagnosis of electrical machines.

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Online Detecting of Inter-Turn Short-Circuit in Generator Rotor Winding Relying on ν-SVR Machine

International Journal of Pattern Recognition and Artificial Intelligence ◽

10.1142/s0218001421500269 ◽

2021 ◽

pp. 2150026

Author(s):

Feng Pan ◽

Xiansheng Guo ◽

Shengwang Pan

Keyword(s):

Prediction Model ◽

Support Vector Regression ◽

Dynamic Simulation ◽

Short Circuit ◽

Back Propagation ◽

Synchronous Generator ◽

Support Vector ◽

Diagnosis Method ◽

Rotor Winding ◽

Online Detecting

To probe an accurate diagnosing approach for synchronous generator (SG) with rotor winding inter-turn short-circuit, a novel online monitoring and detecting method relying on the [Formula: see text]-support vector regression ([Formula: see text]-SVR) machine was proposed, and its effectiveness was further verified by the micro-synchronous generator dynamic simulation. Terminal voltage, active and reactive power of SG were selected as input variables for a novel prediction model based on the [Formula: see text]-SVR, and field current was selected as an output variable of the prediction model. The structures and parameters of the field current prediction model were optimized with the particle swarm optimization (PSO) algorithm and training samples, then the prediction model was established and the field current prediction got under way. By comparing the predicted field current with the corresponding online measured field current, inter-turn short-circuit of rotor winding in SG could be detected sensitively once its absolute value of the prediction relative error exceeded a specific threshold. The micro-synchronous generator dynamic simulation indicated that the proposed online detecting approach based on the [Formula: see text]-SVR machine overcame the shortage of the back-propagation (BP) diagnosis method for misdiagnosis, and its accuracy, sensitivity and threshold setting range of the diagnosis method was the most prominent among these diagnosis methods such as the BP diagnosis method, the Bayesian regularization back-propagation (BRBP) diagnosis method and the [Formula: see text]-support vector regression ([Formula: see text]-SVR) diagnosis method.

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Fault diagnosis of rotor winding inter-turn short circuit for sensorless synchronous generator through screw

IET Electric Power Applications ◽

10.1049/iet-epa.2017.0118 ◽

2017 ◽

Vol 11 (8) ◽

pp. 1475-1482 ◽

Cited By ~ 7

Author(s):

Wu Yucai ◽

Ma Qianqian ◽

Cai Bochong

Keyword(s):

Fault Diagnosis ◽

Short Circuit ◽

Synchronous Generator ◽

Rotor Winding

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Diagnosis of Inter-Turn Short Circuit of Synchronous Generator Rotor Winding Based on Volterra Kernel Identification

Energies ◽

10.3390/en11102524 ◽

2018 ◽

Vol 11 (10) ◽

pp. 2524 ◽

Cited By ~ 12

Author(s):

Luo Wang ◽

Yonggang Li ◽

Junqing Li

Keyword(s):

Volterra Series ◽

Least Squares Method ◽

Early Stage ◽

Short Circuit ◽

Synchronous Generator ◽

Transfer Model ◽

Volterra Kernel ◽

The Time Domain ◽

Rotor Winding ◽

Volterra Kernel Identification

The inter-turn short circuit is a common fault in the synchronous generator. This fault is not easily detected at early stage. However, with the development of the fault, it will pose a threat to the safe operation of the generator. To detect the inter-turn short circuit of rotor winding, the feasibility of identifying the stator branch characteristics of synchronous generator during inter-turn short circuit was analyzed. In this paper, an on-line fault identification method based on Volterra kernel identification is presented. This method uses the stator branch voltage and stator unbalance branch current collected from the generator as input and output signals of the series model. Recursive batch least squares method is applied to calculate the three kernels of Volterra series. When the generator is in normal state or fault state, the Volterra kernel will change accordingly. Through the identification of the time-domain kernel of the nonlinear transfer model, the inter-turn short circuit fault of the synchronous generator is diagnosed. The correctness and effectiveness of this method is verified by using the data of fault experimental synchronous generator.

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Determination of the magnitude of short-circuit surge current for the construction of relay protection on reed switches and microprocessors

Eastern-European Journal of Enterprise Technologies ◽

10.15587/1729-4061.2021.245644 ◽

2021 ◽

Vol 6 (5 (114)) ◽

Author(s):

Alexandr Neftissov ◽

Andrii Biloshchytskyi ◽

Olzhas Talipov ◽

Oxana Andreyeva

Keyword(s):

Magnetic Field ◽

Short Circuit ◽

Relay Protection ◽

Main Element ◽

Current Transformers ◽

Transient Mode ◽

Protection Devices ◽

Aperiodic Component ◽

Surge Current

A study of the functioning of reed switches under the influence of a magnetic field created by a current in a conductor in a transient mode with the presence of an aperiodic component has been carried out. A well-known method for determining current using reed switches was implemented. At the same time, it was determined that the originally formulated method did not give the required result within the limits of errors. This is most likely due to the peculiarities of the mechanism of movement of the reed switch contacts. Alternatively, the measurements were taken to take the return currents instead of the pick-up currents and the time between the return times. They are more stable. Simulation is performed, experimental determination of the value of surge current by measuring time is carried out. The main element of the created installation was the power transformer coil with low active and high inductive resistance. As part of the study, the reed switches were placed in a magnetic field with an aperiodic component, as in the transient mode. This study will show the applicability of reed switches for the construction of relay protection devices that will not need current transformers to obtain information about the primary current in the conductor. In the course of the research, it was found that the error in determining the magnitude of current was no more than 10 %. Using microprocessors, it is possible to build relay protection devices with a speed of up to 20 ms. This result makes it possible to build new devices. Since in the well-known developments, it was only said about determining the magnitude of current in a steady state. When building relay protection devices on reed switches, without using current transformers, it will be possible to build backup protections that duplicate not only the devices themselves, but also the primary measuring transformers with other sensitive elements. This will improve the reliability of the power supply.

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Determination of high power synchronous generator subtransient reactances based on the waveforms for a steady state two-phase short-circuit

Applied Mathematics and Computation ◽

10.1016/j.amc.2017.06.003 ◽

2018 ◽

Vol 319 ◽

pp. 538-550 ◽

Cited By ~ 2

Author(s):

Sebastian Berhausen ◽

Andrzej Boboń

Keyword(s):

Steady State ◽

High Power ◽

Short Circuit ◽

Synchronous Generator ◽

Two Phase

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Simulation of the saturation process of a current transformer with a load

Journal Of Applied Informatics ◽

10.37791/2687-0649-2021-16-4-48-61 ◽

2021 ◽

Vol 16 (4) ◽

pp. 48-61

Author(s):

Kirill K. Krutikov ◽

◽

Vyacheslav V. Rozhkov ◽

Vladimir V. Fedotov ◽

◽

...

Keyword(s):

Power Plants ◽

Short Circuit ◽

Relay Protection ◽

Current Transformer ◽

Dynamic Processes ◽

Current Transformers ◽

Load Mode ◽

Secondary Side ◽

A Current

The article deals with the mathematical basis and simulation of the saturation processes of current transformers with aperiodic components of short-circuit currents. Saturation processes of current transformers can affect the correct operation of the protections. At power plants, in particular atomic ones, the number of current transformers is several hundred with different loads, lengths of supply cables and the implementation of relay protection. At the same time, the determination of the time to saturation is essential for the construction of circuits and principles of construction of relay protection systems and automation of power plants. The dynamic processes in the primary and secondary circuits of current transformers in dynamics are considered in detail. A mathematical description of the dynamic processes of a current transformer in the nominal mode and during a short circuit in its primary circuit is given. The substantiation of the expediency of using the hypothesis of a rectangular magnetization characteristic in simplified calculations of saturation processes is given. The possibility of using the characteristics of magnetization in the test protocols available in practice in the no-load mode to simulate saturation processes has been demonstrated. Simulation of current transformers for the no-load experiment and power supply of the current transformer from the secondary side, as well as during its operation under conditions of a short circuit on the primary side and a known load on the secondary side is carried out. Thus, with the help of a computer experiment, it is possible to take the current- voltage characteristics and transfer them to the model with the saturation of current transformers already in the short-circuit mode. The efficiency of dynamic simulation of current transformers is shown. The software implementation of the model is performed by means of structural simulation in the MatLab package, based on the solution of equations of matrix structures and emulation of parallel computations. It was found that with the adequacy of the model and the real current transformer with the involvement of information from the no-load mode, the determination of the magnetization time from the aperiodic current components from the model is much easier than the analysis by other existing methods. They require detailed design details of the current transformer and the magnetic properties of the steel.

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