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Until now, there is a great development in photovoltaic grid-connected power system. In addition, there is an ongoing research on the problems existed in the system. Islanding of photovoltaic grid-connected power system have adverse impact on power quality and utility equipments, affecting the performance of the utility even worse, it may damage people's lives. Islanding detection is a key consideration...
Self-adaptive system islanding is a new research direction in the field of islanding control. The sub problems and framework of self-adaptive islanding were studied in this paper. The research contents are as follow. First, the traditional out-of-step islanding schemes is introduced and simulated. The simulation results show some defects of traditional islanding. These defects indicate the necessary...
With the development of smart grid future electric grids will operate in an environment where there are increasing renewables, demand responses, and energy storage. Latest information and communication technologies will be deployed in future smart grids to facilitate the transformation. Next generation control centers (NGCC) need enhanced and new monitoring, analysis, and control functions to help...
Major features of IEC 61850 include SCL-based engineering, uniform data model and communication-based information transfer. Owing to XML-based characteristics of SCL, a substation engineering can be done easily with programming. There are four kinds of information file in the SCL-based engineering - SSD (System Specification Description), ICD (IED Capability Description), CID (Configured IED Description)...
Reactive power and voltage control is the important technical means to improve the voltage quality and reduce the active loss of power grid. It is hard to regulate the voltage and reactive power of Guizhou power grid by manual operation. In this paper, adopting to the successful experiences in automatic voltage control (AVC) system of several power companies in Europe and China, a new decomposition...
Electricity Generating Authority of Thailand (EGAT) has developed an in-house Supervisory Control And Data Acquisition (SCADA) system for a decade. The EGAT-SCADA system has been implemented in all regional control centers and substation. Ratchaburi 3 (RB3) is a substation, which was built in year 2000, serving a 4,346.75 MW Ratchauri Power Plant. It is one of a few substations using SCADA system...
Combining with the intelligent monitoring requirements of high-voltage conductor galloping, this paper proposed a design to monitor the conductor galloping parameters. The proposed design could satisfy the demand of frequency-amplitude transforming integration, proposed a honeycomb hexagon model of nodes distribution and a kind of high energy-efficient hierarchical model, it could satisfy the requirement...
Reactive power and voltage control is the important technical means to improve the voltage quality and reduce the active loss of power grid. It is hard to regulate the voltage and reactive power of Guizhou power grid by manual operation. In this paper, adopting to the successful experiences in automatic voltage control (AVC) system of several power companies in Europe and China, a new decomposition...
The transformer is crucial for the energy conversion and transmission in the process of power transmission and distribution, and plays an important role in the security of grid. On-line monitoring and diagnostics provides a promising platform not only to help the operators to manage transformer in a targeted fault repair and maintenance manner, but also to avoid fatal accidents. This paper describes...
Using distributed generation (DG) is an interesting topic that has drawn attention of electrical engineers to itself in recent years. Presence of these generation units in distribution systems, although has many advantages and benefits, has to be applied after performing detailed studies and investigations due to their complexities in operation, control and protection of network. One of the most considerable...
A new differential protection principle for transformer is proposed utilizing calculated power in this paper. It is able to discriminate between inrush and internal fault of transformers with large capacity and extra high voltage, preventing the maloperation due to magnetizing inrush. The calculated power is derived based on two-port network equivalent. An algorithm is presented that is practical...
Time synchronization is the necessary technique to implement automation system in smart substations. It provides the accuracy time stamp mark used for data acquisition and used to analyze and deal with the power system fault. As a type of clock synchronization used in network with high precision, IEEE1588 is widespread applied recently in smart substations. This paper analyzes the reason of clock...
Ethernet passive optical networking (EPON) technology has lots of advantages, which have been implemented in many pilot projects. As the EPON technology's development, we should consider the openness of EPON. In this paper, the great efforts made by the public network operators should be elaborated, but the standard proposed by China Telecom only can meet the basic requirements, and the interoperability...
In order to compensate reactive power and eliminate the negative-sequence and harmonic currents of electrified railway system, a new railway power compensator (RPQC) is proposed. The RPQC consists of three single-phase voltage source converters based on the chain circuit inverters. It connects the railway traction power system directly without isolation transformer. Power rating of the conditioner...
The amount of Distributed Generation (DG - often from renewable energy sources) connected to the UK power system is increasing. This increase has the potential to affect the reliability of protection system operation (a number of instances of protection maloperation have already been experienced [1]). Issues associated with protection that have previously been considered in the literature include:...
Application of Distributed Generation (DG) to supply the demand of diverse customer base has been gaining popularity. Various DGs are connected to the power systems to improve reliability. Conventional distribution system is radial in nature, characterized by a single source feeding a network of downstream feeder. Protection schemes for distribution system have been designed to assume the system to...
A current differential protection criterion based on amplitude and phase difference of fault current is proposed. When fault happens, the amplitude of the fault current component on both sides has nothing to do with the load current, the phase difference won't be influenced basically by transition resistance, distributed capacitance, load current, and the effect of TA saturation is also small, so...
It is hard to determine critical point of voltage stability exactly for some online voltage stability algorithm and its decision-making time is required to be very small, which hinders its practical application on power system. A novel control strategy of voltage stability based on generator dynamic reactive power releasing is presented to deal with the problem. When voltage collapse happens, stator...
Partial discharge (PD) is a common reason that causes electrical breakdown in high voltage underground XLPE cables. This paper proposes a concept of how to build an on-line, on-site system that is able to diagnose the severity of PD activities in XLPE cable as well as differentiate different types of PD signals. The system consists of magnetic probes, low noise amplifier, 3GSPS analog to digital converter...
Today, Ethernet Communication technology is the backbone of Substation Automation. Reliability of the communication connection is crucial. Therefore, known redundancy of Main A/B protection is not good enough in many cases, redundancy of the communication has to be provided. Common Ethernet Media Redundancy systems have a so-called reconfiguration time where the network is busy by itself in terms...
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