The performance triangle in digital substation architectures

In the traditional domain of teleprotection signalling, there is a recognised triangle of performance. This triangle depends upon the required speed of communication, the expected dependability of the command, and the security of receipt. These three aspects are interlinked, and the correct balance of each is required in order to offer the traditional functionality such as permissive signalling, blocking and intertripping schemes. This paper relates the traditional concepts to the application of automation schemes within digital substations. In this manner, it is anticipated that protection engineers can relate today's Ethernet technology by analogy with equivalent trusted practices. Firstly, the paper discusses aspects of speed, particularly in terms of the response required in message-based schemes, and the methods by which integrators can achieve accurate time-synchronising. Secondly, achieving adequate dependability by means of redundancy, and appropriate architectures is treated. Thirdly, security is covered, including aspects of cybersecurity and settings/configuration management.

With the breakthrough of electrooptical technology research on sensor application, the promulgation of IEC 61850, the application of Ethernet communication technology and the development of intelligent breaker, digital substation has become the mainstream of substation automation technology development in future. This paper briefly discusses issues related to electric energy measurement in digital substation, including the differences between electric energy measurement in digital substation and conventional substation, the impact to energy measurement of electronic transformer's application. Meanwhile, aiming at the present issues, potential research fields of electric energy measurement in future digital substation is proposed as well.

Substation is considered as the heart of the power grid where the brain (intelligence) behind the protection, control, automation, monitoring and metering of various parameters related to primary equipment’s are present. At the same time major transformation of grid parameters like voltage, current, frequency, real power, reactive power, power factor, stability etc. is done by various controllers in the substation as per the loading conditions. Over the years, conventional substations have been designed to operate in a rule-based environment. Secondary equipment’s connected and communicated with primary equipment’s and SCADA using hard-wired cables resulted in reducing the overall reliability, safety with increased operational costs. Digital Substations along with Intelligent Electronic Devices (IED’s) has emerged over the past few years along with development of IEC 61850 international standard to design, upgrade and operate the substation in a secure, reliable, and flexible communication mechanism. At the same time various issues related to interoperability, complex engineering processes, ease of maintenance, data handling and reporting has been addressed. Station and Process Bus architectures forms the critical networking hub of digital substations along with intelligent controllers and scalable communications. In this paper, we discuss on overall Digital Substation architecture, case study with special emphasis on Process Bus which is still in the early stages of adoption in Indian grid.

The cost and the reactivity constraints in software development imposed the components technologies as an alternative strategy to traditional software conception. This concept is vital in today's technologies such as Java, DCOM or CORBA 3. One of the interests of these technologies is the ability for applications to use a supporting environment intrinsically distributed and based on. the Internet. However there are still some problems in order to be able to administrate components during their executions. Moreover at the beginning of its development, a component does not know the future hardware and software environment on which it will be executed. Consequently, it is necessary to provide a system support which will offer an adapted execution environment to these components where they can express their own constraints and preferences. In this article, we present some of our specifications for these new services in order to automatically administrate and manage the execution of the application and finally some results of our implementation.

This paper explores need to, a semi-modal of obligation and necessity, and its semantic variation in connection with the sociolinguistic variables of gender, age and social class in the spoken demographic part of the British National Corpus. The semantic/pragmatic uses of need to include internal, deontic, dynamic and epistemic domains based both on traditional concepts and cross-linguistic studies. The sociolinguistic analysis applies the generalisations by Labov, but pays attention to the interactional styles and the communicative needs of the various social groups as well. The results reveal that need to is undergoing change. It shows monotonic distribution among adults, but it is slightly more common among men than women, and, in terms of social class, the upper middle class takes the lead. The semantic variation corroborates these findings – older speakers stick to the more traditional domains – but also reflects the gendered life stages and discourse styles of the speaker groups.