This paper presents learning points from the application of a dynamic thermal rating (DTR) system to a 132kV distribution network. The DTR system incorporates over 90km of 132kV overhead lines and is being deployed to facilitate the connection of in excess of 200 MW of wind generation. The benefits and principles of this DTR system are stated, and initial results from the deployment are presented.The system architecture is discussed and the process by which it evolved from a single-circuit field trial to a geographically disperse system, covering seven meshed circuits, is described. Key elements of the DTR system approach include (i) the system architecture (using intelligent remote terminal units (RTUs) to process and condition the system data); (ii) the system data requirements; (iii) the methodology used for locating the meteorological stations (which underpin the DTR system); (iv) the use of direct conductor temperature sensors to provide additional thermal visibility of the network; and (v) the requirements to ensure that long-term system reliability is maintained, whilst also considering the repeatability of the system for other network areas. The experiences described in this paper may serve as a useful reference for any other DNOs looking to adopt DTR systems.
Members of the Rab3 gene family are considered central to membrane trafficking of synaptic vesicles at mammalian central excitatory synapses. Recent evidence, however, indicates that the Rab27B-GTPase, which is highly homologous to the Rab3 family, is also enriched on SV membranes and co-localize with Rab3A and Synaptotagmin at presynaptic terminals. While functional roles of Rab3A have been well-established, little functional information exists on the role of Rab27B in synaptic transmission.Here we report on functional effects of Rab27B at SC-CA1 and DG-MF hippocampal synapses. The data establish distinct functional actions of Rab27B and demonstrate functions of Rab27B that differ between SC-CA1 and DG-MF synapses. Rab27B knockout reduced frequency facilitation compared to wild-type (WT) controls at the DG/MF-CA3 synaptic region, while increasing facilitation at the SC-CA1 synaptic region. Remarkably, Rab27B KO resulted in a complete elimination of LTP at the MF-CA3 synapse with no effect at the SC-CA1 synapse. These actions are similar to those previously reported for Rab3A KO. Specificity of action on LTP to Rab27B was confirmed as LTP was rescued in response to lentiviral infection and expression of human Rab27B, but not to GFP, in the DG in the Rab27B KO mice. Notably, the effect of Rab27B KO on MF-CA3 LTP occurred in spite of continued expression of Rab3A in the Rab27B KO. Overall, the results provide a novel perspective in suggesting that Rab27B and Rab3A act synergistically, perhaps via sequential effector recruitment or signaling for presynaptic LTP expression in this hippocampal synaptic region.
K E Y W O R D Sneurotransmission, RabGTPase, synapse
This paper addresses the de-risking of real-time thermal ratings (RTTRs) for overhead lines to help build DNO business confidence in the adoption of the technology. Through the use of thermal state estimation with integrated sensors and graceful degradation algorithms, a costeffective RTTR system is being implemented across the 132kV network in North Wales. The system unlocks significant energy yields (up to 14,358 MWh in November 2012 for a single overhead line circuit) whilst minimising the risk of line temperature profile exceedence to a suitably low value.
Active Network Management (ANM) is an effective approach to release more distribution network capacity for connecting renewable generation without expensive network reinforcements. A pilot project is being carried out by ScottishPower Energy Networks in collaboration with Psymetrix new ANM approach on the 33kV distribution network on Isle of Anglesey, North Wales. The new approach is known as Angle Constraint Active Management (ACAM), where a renewable generation is constrained based on voltage angle difference signals produced by Phasor Measurement Units, and a set of angle constraints derived through offline network simulations. ACAM requires fewer measuring devices and simpler control logic than existing ANM solutions, and in this case, 19 potential constraints are managed by 4 angle difference measurements. The paper describes the concept of ACAM, and the progress of the pilot project, including hardware installation and communication setup. The results of angle constraints threshold studies using the network model for controlling future wind capacity addition at selected locations are presented. Based on the results, the benefits of ACAM and potential challenges of implementing PMU-based applications in distribution systems are outlined.
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