Partial discharge (PD) measurements are an important tool for assessing the health of power equipment. Different sources PD have different effects on insulation performance apparatus. Therefore, discrimination between is great interest to both system utilities and equipment manufacturers. This paper investigates use a wide bandwidth on-line measurement consisting radio frequency current transducer (RFCT) sensor, digital storage oscilloscope high personal computer facilitate automatic source...

Partial discharge (PD) signals generated within electrical power equipment can be used to assess the condition of insulation. In practice, testing often results in multiple PD sources. order impact individual sources, must first discriminated from one another. This paper presents a procedure for identification by Starting with assumption that different sources will display unique signal profiles this manifested distribution energies respect frequency and time. Therefore technique presented...

This paper proposes a current sensorless control strategy for the dual active bridge (DAB) converter with nonlinear disturbance observer (NDO)-based load feedforward. The proposed method can regulate both dc-bus voltage and of DAB without sensors. Several performance indexes are established parameter design detailed is presented in this paper. When single-phase H-bridge inverter connected, double-frequency oscillation from feedback path suppressed by proper design, while transient response...

Machine learning techniques have been widely used in transient stability prediction of power systems. When using the post-fault dynamic responses, it is difficult to draw a definite conclusion about how long duration response data should be order balance accuracy and speed. Besides, previous studies problem lacking consideration for confidence level. To solve these problems, hierarchical method based on ensemble classifier multiple support vector machines (SVMs) proposed. Firstly, datasets...

The interturn short circuit of field windings in synchronous machines will cause the current increasing, reactive power output decreasing as well aggravation vibration. In this paper, by using multiloop theory and analyzing steady-state characteristics stator rotor fault currents, expression each loop is obtained, then differential equations system are reduced into linear equations; according to principal that components same frequency equal, solution ac dc can be obtained calculation...

This paper studies the electromagnetic torque (EMT) of a nonsalient-pole synchronous generator with interturn short circuit field windings (ISCFW). First, virtual displacement method serves as basis for analyzing postfault steady-state harmonic characteristic EMT. The interactions among various space magnetic fields different orders, speeds, and rotation directions generated by stator rotor are considered. A general conclusion on EMT characteristics under fault is then derived. Second, based...

In order to maintain the stable operation of power systems, quick and accurate transient stability assessment (TSA) after fault clearance is important. Machine learning methods have been widely used in analysis systems. However, how make good use time series data PMUs effectively balance contradiction between rapidity accuracy brings new challenges TSA. To address this problem, we propose an anti-jitter dynamic evaluation method based on long-short term memory (LSTM) network. model,...

Electric propulsion is widely used in ship systems, and multiphase machines are gaining increasing popularity because of their fault‐tolerant ability, high power density, reduced torque ripple. This study concentrates on the tandem configuration with two 15‐phase induction (IMs) fixed same shaft. Based field‐oriented control reconfiguration for single IM, master–slave coordinated strategy designed motors, which can not only achieve allocation between motors during normal operation, but also...

A sawtooth carrier-based sinusoidal pulse width modulation (SC-SPWM) technique for asymmetrical six-phase two-level inverters is proposed in this paper, which could reduce both the peak-to-peak amplitude and changing frequency of common-mode voltage (CMV). The intersection-plotting method reveals that mirror symmetrical carriers two three-phase groups can help optimize distribution overlapping areas, CMV reduction mechanism SC-SPWM. Additionally, Fourier analysis employed to quantitatively...

Hybrid high-voltage direct current (HVDC) transmission systems employ a new type of HVDC topology that combines the advantages line-commutated converter system and voltage-source system. They can improve efficiency reliability long-distance power transmission. However, realizing alternating-current (AC) grid-fault ride through on inverter side hybrid is challenge considering based (VSC-HVDC) used side. In this study, control strategy for an overvoltage fixed trigger angle power-balance...

To allow utilities to fulfill self-imposed and regulative performance targets that apply them, the demand for new tools help judge health of modern power distribution networks has increased. The analysis partial discharge (PD) signals been identified as a potential diagnostic tool condition monitoring HV plant. In order investigate PD activity produced by range defects within three-phase paper insulated lead covered (PILC) cable under rated conditions, an experiment developed. incorporates...

This paper proposes a novel technique and algorithm for the simultaneous sensing of three-phase currents based on multiple air-core coils. The basic principle current measurement in one conductor using two coils is derived, means self-calibration determined. In order to measure parallel overhead lines, smart sensor has been developed, consisting four located close proximity conductors. Algorithms are simulations extensive experimental verification conducted, first prototype fabricated...

A multiphase annular brushless excitation system is widely used in large-capacity nuclear power units. Accurate fault diagnosis of the rotating rectifier great significance to improve reliability system. However, traditional method based on harmonic analysis stator field current has some deficiencies. In this article, a novel using waveforms and artificial intelligence presented. First, various shape features different faults are analyzed. Then, as input hybrid algorithm dynamic time warping...

A machine learning-based approach is proposed to predict the transient stability of power systems after a large disturbance. The post-disturbance trajectories generator rotor angles are taken as whole cluster, and 19 cluster features defined depict overall characteristics systems. hybrid approach, which combines linear support vector with decision tree, generate final classifier. Comprehensive studies conducted on IEEE 39-bus 145-bus test verify performance approach. Test results show that...

This paper presents a deep learning approach with cost-sensitive loss function for transient stability assessment (TSA). Firstly, multiple generator variables after disturbance are utilized as the original inputs. Secondly, convolutional neural network (CNN) is applied automatic feature extraction and regression model building TSA. The generated TSA can provide more accurate index than fully-connected support vector model. Moreover, proposed to reduce misdetection of instability. Case...

Two signal classification methods have been examined to discover their suitability for the task of partial discharge (PD) identification. An experiment has designed artificially mimic signals produced by a range PD sources that are known occur within high voltage (HV) items plant. The bushing tap point large Auto-transformer highlighted as possible on which attach sensing equipment and is utilized in this experiment. Artificial injected into HV electrode itself frequency current transformer...

Partial discharge (PD) measurements are an important technique for assessing the health of power apparatus. Previous published research by authors has shown that electro-optic system can be used PD measurement oil-filled transformers. A signal generated within transformer may reach a winding and then travel along to bushing core bar. The bushing, acting like capacitor, transfer high frequency components partial its earthed tap point. Therefore, effective current implemented at using radio...

This paper investigates the recognition of partial discharge sources by using a statistical learning theory, Support Vector Machine (SVM). SVM provides new approach to pattern classification and has been proven be successful in fields such as image identification face recognition. To apply classification, data input is very important. The should able fully represent different patterns an effective way. determination features that describe characteristics signals extraction reliable...

Inter-turn short circuit of field windings (ISCFW) may cause the current a generator to increase, output reactive power decrease, and unit vibration intensify, seriously affecting its safe stable operation. Full integration mechanical electrical characteristics can improve sensitivity online monitoring, detect early embryonic period fault small turns. This paper studies calculations variations unbalanced magnetic pull (UMP), which excitation source rotor is basis key monitoring. In grid load...

As the core of large-capacity nuclear power generation system, multiphase annular brushless exciter (MPABE) may cause a serious catastrophe to plant if it fails. In order effectively protect armature winding MPABE, rapid simulation model and sensitive diagnosis method short-circuit (AWSC) fault are studied systematically in this article. First, article proposes general MPABE with AWSC fault. To verify correctness model, corresponding simulations experiments faults carried out, respectively,...