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The following topics were dealt with: energy storage technologies; on-line reliability assessment and control; HVDC and FACTS technologies; communications for distribution system; power transformer; wind farm; SCADA; EMS; power market; power electronics; power system planning; power quality; power system harmonics; power system protection; power system control; power system simulations; substation;...
This paper describes an online temperature measurement system using wireless communication technology. The system is used in a temperature monitor of high-voltage equipments. A low power-consumption CPU and a precise thermo- resistance constitute the circuit of temperature measurement device, which can accurately measure temperature of equipments. To the indoor equipments, the real-time temperature...
For a long time, the discrimination of the inrush current for power transformer is a perplexing problem. In this paper, a new method used to distinguish the inrush current from the inner fault is proposed. Based on sinusoid approximation of instantaneous signal (SAIS), the dynamic magnetizing inductance in the power transformer can be calculated, whose validity is illuminated with two emulating models...
During recent decades, heavy industry (mining, petrochemical, aluminium, pulp and paper ,etc) has installed a large number of static converters for the control of large loads. Nonlinear loads such as traditional diode/thyristor rectifiers with capacitive and inductive loads generate harmonic and reactive current, which leads to poor power factor, low energy efficiency, and harmful disturbance to other...
The state electric power transmission networks of china is experiencing rapid changes and will continue to be operated closer to a stressed condition in which there is substantial risk of cascading outages and blackouts. Major cascading disturbances, or blackouts of these transmission systems can obviously cause severe damage to our society. Based on the concept of self-organized criticality (SOC)...
As for hot gas flow according to fluid equation with interaction with electrical arc and solid chamber, fluid equation must be solved with moving boundary of the chamber and with interaction with hot arc and impurity intrusion. Here we propose application of CIP (cubic interpolated propagation) scheme, which is convenient and good at efficient advection and boundary motion. The CIP code was tested...
Based on a typical fault occurring on a 35 kV transformer, we synthesized three specialties in this this paper: the high voltage test, the relay protection and the oiling testing, and carried on the analysis from the different angle to the identical fault, thus obtained the effective means to handle this kind of trouble. Also this paper proposed how to prevent such accident occurring and safeguard...
Ground flash density (flashs/km2 /year) can reflect the activity of lightning exactly, so it was presented in this paper as a principle to show the thunder distribution in Chongqing region. Based on this principle, thunderstorm distribution electronic map of Chongqing region was programmed, using the data accumulated by the lightning location system in recent years. And this electronic map will be...
Calculation of the maximum injection power is an urgent issue in the planning and operating of wind farms. This paper presents a method based on the stochastic programming theory in calculation of the maximum injection power of large- scale wind farms connected to power systems. It introduces random variables to describe active powers of wind farms because of their stochastic characteristics and pays...
In this paper a method, which is called injection power components theory, for tracing power flow and loss allocation is brought forward. By means of dividing the injection power of sources into components including self-power and mutual-power components and analyzing components' distribution on meshed network, the characteristics of power distribution is given. Firstly, based on the basic circuit...
This paper presents a method to analyze the net-loss costs of transmission. The power component conception is proposed after analyzing the analytic formula of the power source, transmission power and load power. According to the power definition, each power component in the network is allocated to special source. The power component node cost flow conservation principle is used to analyze the net-loss...
Infrared imaging detection is an important method detecting the high-voltage(HV) power equipments running state. It is a kinds of non-contact on-line measurement that can determine the HV power equipment running state, find the fault position and predictive its future state. In the process of the infrared images analyzing, the computer captures remote equipments images, calculates images' moment invariants...
Supercapacitors present many advantages in the energy storage field in comparison with batteries and electrostatic capacitors. To obtain an optimal solution for energy saving, combination schemes of supercapacitors and batteries are worthy of discussion. This paper describes the discharging process of the supercapacitors and some key problems to be solved in applications. Moreover, two methods for...
This paper present the data acquisition system of 20 kVA three phase SMES-based voltage sag restorer device. The control of the voltage source inverter also described . The experimental results show the validation of the data acquisition and the voltage source inverter control system. In the experiment important data of the system is recorded. It can be seen that the system works well in the experiment...
A new method of optimizing under-frequency load shedding (UFLS) is developed in the paper. The main idea is that with the online measurement information of the loads and load-frequency regulation factors, loads with smaller frequency regulation factors are shed earlier than those with larger frequency regulation factors. Therefore the power absorbed by loads will be more effectively decreased and...
Data mining, which is also referred to as knowledge discovery in databases, is the process of extracting valid previously unknown, comprehensible and actionable information from large databases and using it to make crucial decisions. In this paper, we present the data mining process from dissolved gas data extraction to characteristic vectors by grey relational analysis, and corresponding algorithms...
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