Communication Service Model for Wide Area Protection System Based on IEC 61850

In order to meet the requirements of information exchange varieties and manners in wide area protection system, a communication service model based on IEC 61850 is proposed. This service model can realize communication consistency and cooperation between different types of devices. Furthermore, the communication reliability and time delay performance are guaranteed to meet the requirements of relay protection from the upper layer. Message structure of generic sub-station event (GSE) and its communication mechanism are discussed. General methods to communicate digital information by generic substation status event (GSSE) and communicate analog sampling information by sampling analog value (SAV) of GSE are proposed.

Fault area estimation using traveling wave for wide area protection

As the increasing number of Phasor Measurement Units(PMUs) are deployed, wide area protection in power systems has been gaining interest. In particular, fault detection, fault classification and fault area estimation are essential to reduce the damage of faults, and even prevent catastrophic cascades of failures. In this paper, we present a scheme for fault area estimation using PMUs and traveling wave theory. The purpose of this paper is to formulate a scheme for fault area estimation by calculating the approximate fault location based on traveling wave theory.This research has targeted at reliable operation of wide transmission system through the estimation of fault area.To verify the suggested scheme, the various simulations are performed in practical Korean power transmission system.The simulation results show that the proposed scheme has a good performance with high accuracy for estimating fault area.

The research and the development of the wide area relaying protection based on fault element identification

The urgent problem of the relaying protection in the modern AC/DC hybrid connected grid and the development of the wide area communication,the information process and the intelligent technology powerfully promotes the development of the technology of the wide area relaying protection(WARP),which has become a research hotspot that attracts extensive attention.Originated from the basic concept of the wide area relaying protection,this paper analyses the advantages,the effects and the functions of the wide area relaying protection.The two main approaches to realize the wide area protection,which are on-line adaptive setting(OAS)principle and fault element identification(FEI),are introduced in this paper.Aimed at improving the performance of the backup protection,the research content and the technology demand of the wide area protection are proposed,meanwhile,the basic principle and the algorithm of the fault element identification are introduced.At last,the scheme of the limited wide area relaying protection based on the existing pilot channel of the main protection is discussed.

Improving the performance of power system protection using wide area monitoring systems

Wide area monitoring(WAM) offers many opportunities to improve the performance of power system protection. This paper presents some of these opportunities and the motivation for their development. This methods include monitoring the suitability of relay characteristics,supervisory control of backup protection, more adaptive and intelligent system protection and the creation of novel system integrity protection scheme. The speed of response required for primary protection means that the role WAM in enhancing protection is limited to backup and system protection. The opportunities offered by WAM for enhancing protection are attractive because of the emerging challenges faced by the modern power system protection. The increasingly variable operating conditions of power systems are making it ever more difficult to select relay characteristics that will be a suitable compromise for all loading conditions and contingencies. The maloperation of relays has contributed to the inception and evolution of 70 % of blackouts,thus the supervision of the backup protection may prove a valuable tool for preventing or limiting the scale of blackouts. The increasing interconnection and complexity of modern power systems has made them more vulnerable to wide area disturbances and this has contributed to several recent blackouts. The proper management of these wide area disturbances is beyond the scope of most of the existing protection and new, adaptive system integrity protection schemes are needed to protect power system security.

An adaptive limited wide area differential protection for power grid with microsources

The operation mode of power grids with intermittent distributed generations(DGs)changes frequently due to the bidirectional power flow.In comparison with the conventional grids,the protection relays in power grids with micro-sources are more difficult to set.To tackle this problem,this paper proposes an extended bus differential protection(EBDP)strategy based on the limited wide area(LWA).In this method,the micro-grids are divided into several protection areas at the core of the bus.The whole protection areas are protected by the wide area current differential relays,which are also configured to protect each component in this protection area.Moreover,the protection areas can be changed adaptively according to the power flow direction.Finally,a micro-grid model with multiple DGs is developed using the PSCAD/EMTDC platform.The simulation results indicate that the proposed adaptive limited wide area differential protection(LWADP)has better performance than the traditional relaying protection in detecting the faulty area in micro-grids and isolating the fault,and can be widely utilized in larger micro-grids.

Developments of power system protection and control

Synchronized wide area communication has become a mature technology,which makes the real-time interaction between the substations and the wide area protection and control system possible.However,the present protection and control system to handle this real-time data has been recognized to be deficient.This paper begins by reviewing the development history of power system protection,with special attention paid to the recent development in the field of wide-area and integrated protections,in order to look into the future development of protection and control systems.Then the concept of integrated wide area protection and control is introduced,where it can be shown that a hierarchical protection and control system provides the protection and control for wide area or regional power substations/plants and their associated power networks.The system is mainly divided into three levels:the local,the substation/plant,and the wide area/regional.The integrated functions at each level are described in details with an aim to develop an optimal coordination mechanism between each level.The key element in the proposed system is the wide area real-time protection and control information platform,which not only enables the merger of three lines of defence for power system protection and control,but also provides a perfect tool for the application of cloud computing in substations and power networks.

Hierarchical protection control system of smart substations

This paper analyzes the problems of the relay protections and secondary circuits of traditional substations,and introduces the hierarchical protection and control system of smart substations based on the technologies like IEC 61850 Standard,electronic instrument transformer,process level network,and wide area optical fiber communication network,etc.The hierarchical protection and control system includes three levels:local area protection,substation area protection and control,and wide area protection and control.These three levels are combined to solve the problems of the relay protections in traditional substations,thus improving protection performance and control capability of the system.

Smart Power Substation Development in China

Over the past decade,China has undertaken substation intellectualization of more than 2000 substation operations in three stages.Much experience has been achieved during this developmental period.In this paper,the status of smart substation development in China is systematically presented,as well as future directions of the smart substation,such as adoption of the hierarchical protection and control system.