This paper focuses on a hybrid islanding detection algorithm for parallel-inverters-based microgrids. The proposed algorithm is implemented on the unit ensuring the control of the intelligent bypass switch connecting or disconnecting the microgrid from the utility. This method employs a grid impedance estimation technique that uses resonance excitation once grid fault occurs. It includes two st...

Using the even-odd mode anafysis of four-port networks with double symmetry, the scattering parameters of the microstrip-slot coupler are derived from the evenand odd-mode parameters of the coupler cross section. The uncompensated coupler and the coupler compensated by extending tbe slot fines are treated and desigo specifications are given covering the compensation slot lines. A comparison wit...

in this research, the physico-chemical water quality parameters and the effect of climate changes onwater quality is evaluated. during the observation period (5 months) physico-chemical parameterssuch as water temperature, turbidity, saturated oxygen, dissolved oxygen, ph, chlorophyll-a, salinity,conductivity, and concentration of total nitrogen (nutrient level) as main pollutant factor have be...

This paper discusses the physical meaning and properties of the waves defined by v%+ z%Ib ~ = V. – Z,*Ii a%= ,, 2u/Re Z,] 2<1 ReZtl where V, and 1, are the voltage at and the current flowing into the ith port of a junction and Z, is the impedance of the circuit connected to the ith port. The square of the magnitude of these waves is directly related to the exchangeable power of a source and the...

Increasing numbers of wind turbines are being erected. In the near future, they may start to influence the dynamics of electrical power systems by interacting with conventional generation equipment and with loads. The impact of wind turbines on the dynamics of electrical power systems therefore becomes an important subject, studied by means of power system dynamics simulations. Various types of...

A design of 3 dB compact ultra wideband (UWB) coupler for a 4 × 4 Butler Matrix, which is operating between 3 and 11 GHz frequency range, is presented in this paper. The proposed design uses multilayer technology that allows having a compact and broad bandwidth coupler. The design uses elliptically shaped broadside coupled strips and a slot created in a common ground plane of two dielectric sub...

Virtualization technology in Cloud computing has become important technology to reduce power consumption in data centers. Virtual Machine allocation to hosts is the main concept which carried out during Virtual Machine migrations in data centers. Virtual Machine allocation helps to utilize hardware resources of hosts and leads to power efficiency in Data centers. In the past few years, various ...

This paper aims to design an energy efficient Medium Access Control (MAC) for IEEE 802.15.4 based Wireless Sensor Networks (WSN). This is achieved by replacing the currently existing common-range maximum transmission power with the concept of dynamic and adaptive transmission power control. Various parameters like Link Quality, Received Signal Strength, MAC collisions, are considered for exerci...

This paper presents a laboratory study on ‘effects of integration of induction generators on grid power quality parameters such as voltage, frequency power factor, harmonics and reactive power’. Study is carried out with different switching sequence of grid connected induction generators. The analysis is done with two squirrel cage induction generators and one wound rotor induction generator co...

Five key UMTS radio network parameters are simultaneously optimized with an automatic control method. The parameters relate to admission control, power control, handover control, and coverage. The optimization is guided by heuristic expert-defined rules, which apply specific trade-off policies and statistics of poor quality calls, blocking rates, power and interference levels, and terminal meas...