Droop control of converter-interfaced microsources in rural distributed generation

This paper proposes new droop control methods for load sharing in a rural area with distributed generation. Highly resistive lines, typical of rural low voltage networks, always create a big challenge for conventional droop control. To overcome the conflict between higher feedback gain for better power sharing and system stability in angle droop, two control methods have been proposed. The first method considers no communication among the distributed generators (DGs) and regulates the converter output voltage and angle ensuring proper sharing of load in a system having strong coupling between real and reactive power due to high line resistance. The second method, based on a smattering of communication, modifies the reference output volt-age angle of the DGs depending on the active and reactive power flow in the lines connected to point of common coupling (PCC). It is shown that with the second proposed control method, an economical and minimum communication system can achieve significant improvement in load sharing. The difference in error margin between proposed control schemes and a more costly high bandwidth communication system is small and the later may not be justified considering the increase in cost. The proposed control shows stable operation of the system for a range of operating conditions while ensuring satisfactory load sharing

Improved power sharing among distributed generators using web based communication

This paper investigates the possibility of power sharing improvements amongst distributed generators with low cost, low bandwidth communications. Decentralized power sharing or power management can be improved significantly with low bandwidth communication. Utility intranet or a dedicated web based communication can serve the purpose. The effect of network parameter such line impedance, R/X ratio on decentralized power sharing can be compensated with correction in the decentralized control reference quantities through the low bandwidth communication. In this paper, the possible improvement is demonstrated in weak system condition, where the micro sources and the loads are not symmetrical along the rural microgrid with high R/X ratio line, creates challenge for decentralized control. In those cases the web based low bandwidth communication is economic and justified than costly advance high bandwidth communication

Structural Clones of UAG Decoding RNA

Functions of non-coding RNAs are related in part to their secondary structures. We investigate the uniqueness of the secondary structure of a non-coding RNA (ncRNA) decoding UAG to read pyrrolysine (pyl). Nineteen archaeal methanogens are searched with our tRNA-pyl-tracker, TPYLT, pert-script downloadable from www.gyanxet.com. We observe that aside from the usual pyl-gene-cluster, pyl-carrying Methanosarcinaceae have a good number of conjugate-halves from pyl-tRNA (pylT) gene split at 37/38 spread over their genomes. On insilico ligation, the secondary structures of these pairs clone the clover-leaf of pylT of M. barkeri. Of these nineteen methanogens, four, namely, M. stadtmanae, M. kandleri, M. hungatei, and M. thermautotrophicus, have these pairs at levels at or higher than in the pyl-carrying ones. Screening these we arrive at four pairs, i.e., one from each of these four genomes. On ligation, these are close homologs of pylT gene of M. barkeri. The intervening sequences between the split pairs in these four cases are shown to nearly reproduce the known secondary structures at exon-intron boundaries