GPS Time Synchronization Research Articles

스마트그리드를 위한 자율형 상태관측기 연구

In this study, authors have proposed the autonomous state estimation which has been composed with IEC61850, GPS time synchronization and objective model design concept. The proposed method is able to supervise/correct measurement and communication error from SCADA. The major advantages of the proposed autonomous state estimation are that it is possible to evaluate integrity of data measured and transferred from SCADA, to reduce human intervention and to expense national-size applications such as EMS (Energy Management System), WAMS (Wide Area Monitoring System) or WAPS (Wide Area Protection System). This study addresses the issues related to the operation of the smart grid and proposes a new automated approach to achieve this goal. Through applying the proposed system to IEEE 14-bus test electric system, we prove the possibility of the proposed idea.

WALTA school-network cosmic ray detectors

The Washington Area Large-scale Time coincidence Array (WALTA) is placing particle detector arrays in secondary schools in the Seattle area to build up a large-scale ultra-high energy cosmic ray detector network, one of several such projects around the world. Scintillation counters salvaged from the CASA experiment in cooperation with the CROP group at the University of Nebraska at Lincoln are refurbished by teachers and students, tested, calibrated, and installed in four-fold arrays at high school sites. To identify time coincidences, a GPS time synchronization system is employed. Data are acquired using a custom low-cost DAQ card. Here we will describe the logistics and status of WALTA and show samples of data taken with a prototype array at the University of Washington.

Focus on Data Acquisition

Focus on Data Acquisition

Evaluation of lightning location data employing measurements of direct strikes to a radio tower

A lightning location systems (LLS) provides large scale information for lightning strikes to ground. In addition to the event time and strike point position, the LLS gives estimates for the lightning peak current. For the end user of LLS data it is important to know the technical limits of the applied network in terms of detection efficiency, accuracy of the stroke location and peak current estimate. To establish a ground truth reference for comparison of natural lightning current parameters and the data of ALDIS (Austrian Lightning Detection & Information System), a telecommunication tower on Gaisberg near the city of Salzburg (Austria) was instrumented for direct lightning current measurement. Since the start of the tower experiment in 1998 we have recorded more than 200 lightning flashes to the tower. Based on the analysis of the current waveforms nearly all of them are so called upward initiated discharges. GPS time synchronization of both data sets allows a precise correlation of individual events measured at the tower and reported by the lightning location network.