Protection and Control of Active Distribution Networks and Microgrids

This thesis is mainly focused on (i) modeling and control of Electronically Coupled Distributed Energy Resources (EC-DERs) under severe network imbalances and transient incidents, and (ii) protection of active distribution networks and microgrids against different types of faults. In the first part, an enhanced control strategy is proposed to improve the performance of EC-DERs under faults and transient disturbances, in a multi-unit microgrid setting. With the use of proposed control strategy, the host microgrid can ride through network faults, irrespective of whether they take place within the microgrid jurisdiction or impact the upstream grid, and quickly reclaim its pre-fault operating conditions to improve post-fault recovery. Further, the proposed control scheme enables the host microgrid to retain its power quality for the duration of the faults, in both modes of operation, which is a desirable property for detection of certain classes of faults, as well as for sensitive loads. In the second part of the thesis, appropriate strategies are proposed for protection of low- and medium-voltage microgrids in the islanded mode as well as the grid-connected mode of operation. The proposed protection strategies aim to detect and isolate the faults that impact the microgrid, in a selective manner. The proposed strategies can be implemented through programmable microprocessor-based relays which are commercially available; hence, the structure of new relays that enable the proposed protection strategies are also discussed in the thesis. In addition, the thesis investigates the operation of an existing distribution network as a microgrid. Thus, practical control and protection strategies that enable off-grid operation of the distribution network (considering the system constraints) are discussed. The effectiveness of the proposed control and protection strategies are demonstrated through time-domain simulation studies conducted in the PSCAD/EMTDC software environment

The Role of Glycoproteins in Neural Plasticity in Domestic Chick

In this project various neurochemical and immunological approaches were used to identify and analyse the role of glycoproteins in neural plasticity. Where appropriate, the one-trial passive avoidance paradigm was used (Gibbs & Ng 1977). Initially, the role of a glycosylation inhibitor, 2-deoxy-D-galactose (2DGal), was examined both in vivo and in vitro. The results of these studies agreed with previous reports that 2DGal inhibits incorporation of fucose and galactose into glycoproteins. However, 2DGal inhibited fucosylation and galactosylation of only a sub-set of these macromolecules. The localization of these glycoproteins in synaptic plasma membranes (SPMs) and postsynaptic densities (PSDs) suggested differential glycoprotein synthesis and distribution across the synaptic cleft. Subsequent studies attempted to identify the fucosylglycoproteins involved in learning and memory formation and to characterize their structure, sub-cellular distribution and the timecourse of their expression. An in vitro increase in the rate of fucosylation was found in the right forebrain base after training. Further, the rate of fucosylation of a protein component of Mr 110-120kD increased significantly within the first four posttraining hours. A number of glycoproteins showing significant increase in fucosylation either 6hr or 24hr after training, or at both posttraining time-points were identified in vivo. Most were concentrated in SPMs and PSDs of LPO as summarised in figure A.1. Polyclonal antibody R15 was raised and it recognized a 60-62kD antigen in SPM and PSD fractions. It rendered chicks amnesic when injected bilaterally 30min before training. Immunocytochemical studies showed medium density labelling of axonal membranes and SPMs and PSDs. Finally, the sugar contents of SPM and PSD membrane-bound glycoproteins were analysed using specific lectins. Chick brain glycoproteins were separated by two-dimensional gel electrophoresis and identified using the lectin Ulex Europaeus type I (UEA.I). Some 55 fucosylated polypeptides were found in SPMs and PSDs. Specific antibodies whose antigens have been implicated in learning and memory formation were used to examine whether their immunoreactivity changed as a result of passive avoidance training. Both anti-N-CAM antibodies and anti-ependymin antibodies cross-reacted with chick antigens from SPM and PSD fractions, but immunoblotting did not show training-induced changes. The results reported in this thesis are discussed in the light of current understanding of neural mechanisms of learning and memory. Several hypotheses are considered which collectively recognize glycoproteins as major contributors to neural network formation/re-formation during learning and formation and consolidation of memory

ANTIQUE: A Non-Factoid Question Answering Benchmark

Considering the widespread use of mobile and voice search, answer passage retrieval for non-factoid questions plays a critical role in modern information retrieval systems. Despite the importance of the task, the community still feels the significant lack of large-scale non-factoid question answering collections with real questions and comprehensive relevance judgments. In this paper, we develop and release a collection of 2,626 open-domain non-factoid questions from a diverse set of categories. The dataset, called ANTIQUE, contains 34,011 manual relevance annotations. The questions were asked by real users in a community question answering service, i.e., Yahoo! Answers. Relevance judgments for all the answers to each question were collected through crowdsourcing. To facilitate further research, we also include a brief analysis of the data as well as baseline results on both classical and recently developed neural IR models