In this paper it is shown that M class PMU (Phasor Measurement Unit) reference model for phasor estimation recommended by the IEEE Standard C37.118.1 with the Amendment 1 is not compliant with the Standard. The reference filter preserves only the limits for TVE (total vector error), and exceeds FE (frequency error) and RFE (rate of frequency error) limits. As a remedy we propose new filters for phasor estimation for M class PMU that are fully compliant with the Standard requirements. The proposed filters are designed: 1) by the window method; 2) as flat-top windows; or as 3) optimal min-max filters. The results for all Standard compliance tests are presented, confirming good performance of the proposed filters. The proposed filters are fixed at the nominal frequency, i.e. frequency tracking and adaptive filter tuning are not required, therefore they are well suited for application in lowcost popular PMUs.
For the reason of environmental problems connected with the use of furan binders, attention is increasingly being paid to self-setting mixtures using alkali resols. A resol binder stabilized with KOH, NaOH is hardened by liquid esters with the formation of alkaline salts. The increase of their concentration affects the shortening of the mixture bench life, it also decreases strength, increases abrasive wear to moulds and cores, and results in uneconomical dilution of the reclaim with expensive new base sand. The length of life (bench life) of mixtures plays an important role in the manufacture of huge and voluminous moulds and cores in self-setting mixtures. This study aims at analyzing the function of reactive alkaline salts in the reclaim, monitors the consequences of its thermal exposure on the properties of selfsetting mixtures, and deals with development of methods evaluating its qualities.