from heavy demand areas. Growing power demands are mainly Abstract-New SVC was commissioned in March 2005 at commercial not industrial, i.e. represented by air-conditioners, MUSSAFAH 400kV/220kV substation in Abu Dhabi, UAE. The they are constant active power loads and tend to absorb more capacity of the SVC is +/-200MVA. The SVC consists of two reactive power when system voltage is lower. identical SVCs of +/-lOOMVA connected to 220kV bus, and they are operated as independently or in parallel. This SVC is located As far end of the 400kV network is connected to power near heavy load center with air-conditioner characteristic loads then the SVC design was carried out carefully. The SVC provides plantos Th e2ofkV circuit is mai ned by a Vr of * (capacitive) and -3OMVA (inductive) were obtained from the M. Ibrahima and A. A. Atia are with TRANSCO, Abu Dhabi, United Arab steady state analysis. Emirates 173 (

No abstract

This paper reports on the successful relocation and reconstruction of an existing Static Var Compensator (SVC). In 1987, for experimental test purposes, an SVC with a controlled rating of 100 MVAr was installed in the Shin-Shinano 50 Hz-60Hz frequency converter (FC) substation, on the 50 Hz, 500 kV side, to help control the voltage of the transmission network. Certain components of this test SVC were removed from service and returned to the factory to customize the design to meet the requirements of a new application, and to update and modify the equipment to meet the latest commercial operating requirements.This reconstructed SVC was installed in the Suruga substation, on the 154 kV side. In 2001, the SVC was successfully tested to verify its correct operation and application.

At present, most of all inverters used in UPS are voltage-source types. In this case, a series reactor is an essential component of the output filter of the inverter because the waveforms of the output voltages consist of trains of voltage pulses. One of major issues of this type of system is magnetic noises, which are produced by the output voltage and appear at the series reactor and the output transformer.The use of the current-source inverter has merits not only reducing noises when compared to the case of voltage-source type but also getting a quasi-sinusoidal output voltage without any series reactors. However, there are few cases of applying the current-source inverters to the UPSs because built-in batteries of constant voltage are utilized as a voltage supply in the system.The feasibility of applying the current-source inverter to the UPSs is attempted in this paper, and a new circuit topology suitable for the UPSs is proposed. At the output terminal of the inverter only a capacitor is connected in parallel with a load, and the output voltage of the inverter is controlled so as to make it coincide with reference sinusoidal voltage. In order to realize this strategy, two choppers have to be connected between the DC input voltage source and the inverter.After showing the circuit configuration, the validity of the proposed method is confirmed by means of both simulation and measurement. When this type of the inverter is applied to an UPS, the waveforms of the inverter output voltage and the switching frequency depend strongly on the circuit constants and output voltage error. Then, these are discussed in quantity to get a design guide. A comparison with conventional current-source inverters shows that the new inverter system has a plenty of merits.