A5047491847- Power Systems Fault Detection
- High-Voltage Power Transmission Systems
- HVDC Systems and Fault Protection
- Advanced materials and composites
- Microstructure and Mechanical Properties of Steels
- Metal Alloys Wear and Properties
- Brake Systems and Friction Analysis
- Islanding Detection in Power Systems
- Lightning and Electromagnetic Phenomena
- Smart Grid and Power Systems
- Electromagnetic Compatibility and Noise Suppression
- High-pressure geophysics and materials
- Catalysis and Oxidation Reactions
- High voltage insulation and dielectric phenomena
- Power System Optimization and Stability
- Crystal Structures and Properties
- Power Systems and Renewable Energy
- Power Transformer Diagnostics and Insulation
- Power Systems and Technologies
- Magnetic Bearings and Levitation Dynamics
- Railway Engineering and Dynamics
- Climate Change Policy and Economics
- Thermal Analysis in Power Transmission
- Thermal Expansion and Ionic Conductivity
- Peripheral Nerve Disorders
Hefei University of Technology
2024
Tongren Hospital
2024
Shanghai Jiao Tong University
2024
Shanghai University of Engineering Science
2021-2022
Shanghai Laser Technology Institute
2021
North China Electric Power University
2005-2020
China University of Mining and Technology
2018-2020
Princeton University
2018
Beijing Automotive Group (China)
2008
<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A traditional distance protection relay uses a lumped parameter model of the transmission line. For long 1000-kV UHV line with large distributed capacitance, such simplified is inadequate and can cause malfunction due to errors in impedance measurement. This paper presents new for procedure reliable fault measurement setting. It describes proposed application developed 645-km including shunt...
In substations with an inner bridge connection, the two main transformers are generally connected in parallel. The differential protection of transformer, under normal operating conditions, may maloperate when other transformer is switching on through breaker after scheduled maintenance. This paper analyzes factors that lead to maloperation and concludes local transient saturation current (CT) caused by decaying dc component magnetizing inrush cause protection. By detecting time difference...
As the conventional relay usually takes bus voltage as a polarizing voltage, its operating characteristic is fixed and cannot adapt to fault resistance. To enhance capability against resistance, based on compensated changing with kind of adaptive impedance composite presented in this paper. On other hand, boundary may enter into an ldquoinphaserdquo area along increase prevent from maloperation area, new additional blocking component also proposed. Both were all analyzed plane plane....
When a fault occurs on transmission line, fault-generated high-frequency signals contains lot of information about fault. This paper proposes location scheme for lines based spectrum characteristic components, the difference adjacent two natural frequencies in one ends line is used to compute distance. method need not identify arriving time first traveling wave and from point, it insensitive swings, type, resistance system source parameters. The performance was proven using power computer...
In order to accurately measure the impedance, residual current for impedance measurement in ground distance relay is compensated a fixed manner. It has been shown that above compensation manner may have negative impact on phase selection mho elements single-pole trip scheme. A new method based magnitude of each presented this paper. The performance analyzed under all kinds fault conditions. Simulation studies are carried out investigate component typical transmission system. satisfactory...
When faults occur in transmission lines, the high frequency signals are caused by fault generated traveling waves and spectrum is a series of harmonic domain. This paper utilizes lumped distributed parameter models to express lines respectively, analyzes character nature frequencies. Different influencing factors including different conditions, source impedance, bus capacitance, compensated capacitance shunt reactor discussed this paper. The results have been proven ATP procedure typical...
Cascading trips caused by flow transferring are crucial for lots of well-known blackouts. For a power system with heavy load flow, once there is fault, the might suffer after fault clearing. However, relays, they cannot know sensing overcurrent internal faults or transferring. The relays will trip predefined time delay, which result in again and worsen state. Therefore, if pickup due to transferring, back-up relay should be blocked until thermal limit line reaches. In this paper, Flow...
According to the disadvantages of serious wear and heat fade friction pad in frequent high speed braking brakes, insufficient power electromagnetic brakes low braking, a novel frictional-electromagnetic compound disk brake which combines both these two principles is proposed for automotives this paper. The excitation coils are designed based on Zhang Yicheng theory model, prototype manufactured self-made magnetic pads existing automotive brakes. field dynamic simulated by using COMSOL...
Protective relays, pivotal devices that can quickly identify and isolate fault area in power systems, is of great importance for network security reliability. When relays trip a faulted line the network, flow on will be transferred to other lines. Those lines might overloaded then cascading tripped by backup which worsen system state even cause blackout. Studies several well-known blackouts reveal protective are involved most troublesome ones relays. In this paper defects existing...
To avoid the mal-operation of transformer differential protection when external fault occurs with current (CT) saturation, a new algorithm based on mathematical morphology is put forward in this paper. Unlike conventional Time Differential Method, only needs detecting instant occurring, while appearance no more needed. A waveform obtained by symmetrical transformation initial part after occurrence, and then its characteristic exacted morphological gradient. In case CT serious discrimination...
This paper proposes a fault classification scheme for transmission lines based on spectrum of component. First it analyses the component, then characters power frequency and nature frequencies in two data windows are used to identify type phase respectively. The performance was proven using ATP/EMTP simulations 500-kV system considering different types locations. results show that works quickly is not impacted by harmonics DC offset. It also sensitive sampling rate inception angle.
<title>Abstract</title> <bold>Background</bold> This study assessed the medical effectiveness and cost-effectiveness of a multidisciplinary team (MDT)-based interventional follow-up in managing hypertension, thereby serving as an evidence base for decision-making disease prevention control community residents. <bold>Methods</bold> We randomly assigned 5,676 residents Shanghai’s Changning District to intervention or group followed them up two years. <bold>Results</bold> The mean BP decreased...
Motivation: Gliomas are the most common type of central nervous system tumors in children, and histological classification plays a crucial role determining prognosis treatment. A non-invasive approach is needed for pre-surgery characterization histopathology tumor. Goal(s): The aim this study was to explore feasibility applying time-dependent diffusion magnetic resonance imaging (td-dMRI) parameters discriminating between high-grade gliomas (HGG) low-grade (LGG). Approach: Nine pediatric...
When a fault occurs on transmission line, fault-generated high-frequency signals contains lot of information about fault. This paper proposes protection scheme for phase-to-phase in line based spectrum characteristic signals. The difference fundamental natural frequencies both ends is used to determine whether internal or external. can reduce trip time if the an and does not misoperate It also identify chose-up faults. performance was proven using Power System Computer Aided Design (PSCAD)...
The equivalent circuits modeling method is developed for the EMP(Electromagnetic pulse) generators of equipment-level immunity test. On double-exponential function EMP waveform, corresponding circuit structure introduced, and calculation given to obtain RLC parameters. For EFT(Electrical Fast Transient/Burst), surge combination wave, ESD(Electro-Static Discharge), components parameters are proposed. Finally, simulation results validate proposed models.
In this paper, a new fault diagnosis model based on Petri net is put forward. The detailed Net models and relevant inference process are presented. proposed system can locate the elements fast accurately, generates reliable effective results automatically. It be applied in power grid for not only simple fault, but also multiple faults or severe composed of protective devices incorrect operation. This good online system. practical test Siping shows that practicable