With the increasing scale of wind farms, fault characteristics tend to be complex, which poses a technical challenge establish dynamic equivalent model farms. In this paper, method DFIG-based farm based on density peak clustering algorithm (DPCA) is presented. First, under an analysis short-circuit current (SCC) in single doubly fed induction generator (DFIG), indexes are selected. Second, with selected and DPCA, more refined two-stage DFIGs carried out. Third, units same cluster one unit,...

Partial discharge (PD) is an early manifestation of multiple cable faults. The traditional PD monitoring method has a weak effect and low positioning accuracy when the cable. This paper proposes distributed on-line for based on phase-sensitive fiber-optic time domain reflection (φ-OTDR) principle. Firstly, production propagation model partial ultrasonic wave (PDUW) was established simulated, distribution PDUW inside with different conditions structures obtained. Then we PDUW, backscattered...

Broadband impedance spectroscopy (BIS) has become a new method for detecting cable insulation defects, but the sensitivity of this to local defects in cables not been fully studied. Taking long submarine as an example, firstly, intrinsic correlations between characteristics and parameters are studied, influence on peak spectrum is studied by establishing simplified model with defects. Secondly, formula calculating input proposed Finally, different positions degrees at first resonant...

This paper presents a calculation method of short-circuit current (SCC) for doubly fed induction generator (DFIG)-based wind farm considering the voltage distribution characteristics. When fault occurs in farm, large SCC will be contributed by dozens or even hundreds DFIGs farm. And security and stability affected SCC. The characteristics DFIG are closely related to its post-fault terminal (PFTV). Therefore, practical model single is proposed this paper, based on electromagnetic transient...

The burgeoning demand for enhanced power-system safety means that there is increased attention on technologies the detection and location of cable faults. double-terminal fault method, which senses a current using transformer (CT), most effective widely applied method in industrial practice. However, CT sensors may suffer from magnetic saturation when exposed to high current, resulting significant errors, their sensitivity cannot be adjusted. To address this problem, paper describes an...

Abstract Partial discharge (PD) diagnosis is a crucial tool to assess the insulation condition of wind farm cables. Among PD techniques, localisation promising as it can provide target maintenance indicators on weak points Accordingly, this paper developed portable detection and location system for inter‐array The consists two non‐invasive lightweight testing units, which be conveniently deployed an energised cable, enabling highly efficient online widely distributed achieves accurate cable...

The behaviours of induction motor, even the lifetime, are strongly depending on power supply quality, such as voltage sags, harmonics and unbalance. winding temperature increase resulting to insulation breakdown has been considered one major causes motor failure. This paper investigates lifetime impact fluctuations particularly operating reduction which is contributed from stator current variation characteristic. Additionally, expectancy analysis with different load level also represented...

Identifying the location of partial discharges (PDs) and providing clear information on insulation vulnerabilities in power systems can help utility companies to improve their maintenance efficiency. This paper presents a PD monitoring locating system for medium-voltage switchgears using set transient earth voltage (TEV) detectors. A time-of-flight methodology was used identify switchgear affected by among row switchgears. time sharing access mechanism, which implemented multiple...

The effective pattern recognition of cable partial discharges (PDs) enables prompt corresponding measures to ensure safety. Traditional PD monitoring methods have limitations in online and accurate positioning, the feature extraction monitored electrical signals requires significant prior knowledge. Therefore, this paper reports performance distributed optical-fiber vibration-sensing PDs on a with different insulation defects, proposes data-driven approach based signals. time series...

Partial discharge (PD) testing has proven one of the effective methods to evaluate operation condition 10-kV covered conductor (CC) lines and predict permanent faults. Power utility technicians usually patrol CC with ultrasonic devices seek PDs. Although this strategy is effective, it costly time consuming for utilities manage vast distribution network. Therefore, objective paper develop a practical PD locating system enhance maintenance efficiency lines. A novel double-sided traveling wave...

Top oil temperature (TOT) is an important indicator reflecting the load capacity and insulation aging of transformer. In order to predict TOT accurately, this paper propose a transformer top prediction method based on BP neural networks optimized by Adam. Firstly, we use grey relational analysis calculate correlation between other state variables TOT, select with larger as inputs output establish model (NNPM) TOT. Next NNPM trained using historical data Adam optimization algorithm. Then case...

Abstract A method of reconstructing the original partial discharge (PD) signal to improve accuracy PD localization in cross‐linked polyethylene (XLPE) cables is presented here. XLPE cables, extremely sensitive PDs, are most popular underground urban grids. The conventional methods, based on evaluation arrival times pulses time domain, negatively affected by dispersion and attenuation signals propagating power cable. for accurate PDs realized through inverse frequency domain modelling (IFDM)...

With the continuous development of HVDC technology, increase in number ports MTDC system and increasing complexity network topology, deficiency traditional flow calculation method is becoming clear. In this paper, a power that contains distribution VSC-MTDC mixed which based on asynchronous iterative put forward. On basis current model converter, by dividing hybrid coordinating boundary variables, achieves global convergence whole system. The shortcomings numerous converter stations method,...

Off‐line partial discharge (PD) diagnosis, which requires an additional power supply has been accepted as essential step in ensuring the integrity of cable systems during commissioning testing. Many types energizing voltage sources (e.g., alternating current resonance, damped current, very low frequency [VLF] sine, and VLF‐cosine rectangular) have developed, are used practice. However, choosing optimal waveforms for PD testing is still controversial because their capability to motivate...

When the short circuit occurs in a wind farm, generator terminal voltage drops of doubly fed induction generators are different and have great impact on short-circuit currents contribution generators. Firstly, practical calculation model for correction method topology matrix farm under symmetrical presented this paper. And then, DFIG-based farms considering distribution is obtained. Finally, accuracy verified by time domain simulation. Moreover, values obtained way compared to from national...