microgrid presents an efficient and novel solution for integrating many new energy generating resources with traditional distribution networks. having an appropriate protective scheme is a fundamental challenge in achieving microgrid plans. it is proven that traditional protective plans are not efficient for protecting microgrid, since the network is dynamic and the level of fault current chang...

 The resonance between power-factor-correction capacitors and the line reactance is a common cause for harmonic problems in traditional power systems. Grid-connected inverters integrating renewable energy sources into the grid exhibit capacitive output impedance at harmonic frequencies and may also resonate with the grid impedance. In addition to possible amplification of current and voltage ...

Considering the effect of the utility harmonic impedance variations on harmonic responsibility, a method based on piecewise bound constrained optimization is proposed in this paper to evaluate the load harmonic responsibilities. The wavelet packet transform is employed to determine the change times of the utility harmonic impedances. The harmonic monitoring data is divided into several segments...

The small-signal impedance modeling of modular multilevel converter (MMC) is the key for analyzing resonance and stability of MMC-based ac power electronics systems. MMC is a converter system with a typical multi-frequency response due to its significant steady-state harmonic components in the arm currents, capacitor voltages, and control signals. Therefore, traditional small-signal modeling me...

studies show that any complications including hemorrhage, lack of blood supply, lack of oxygen supply, and death of cells in a tissue, will have a clear effect on electrical properties of that tissue. thus, by measuring impedance of a set of tissues, potential problems of the damaged tissue may be found. since electrical impedance is closely related to the measuring frequency, obviously, every ...

Mains impedance is a critical parameter to consider when diagnosing load generated power quality problems. High impedance can contribute to voltage sags, low voltage conditions, high frequency noise, transient impulses, and harmonic voltages. These problems can be created by the critical load, or by other loads powered from the same electrical source. This paper presents the concept of mains im...

In this paper, a new approach is proposed for voltage and current harmonics compensation in grid-connected microgrids (MGs). If sensitive loads are connected to the point of common coupling (PCC), compensation is carried out in order to reduce PCC voltage harmonics. In absence of sensitive loads at PCC, current harmonics compensation scenario is selected in order to avoid excessive injection of...

Short Abstract—A simplified inverse class F power amplifier (PA) with a voltage second harmonic peaking and third harmonic short operating at 2.14GHz for WCDMA base station applications has been developed. The load network is based on transmission line harmonic traps and provides high impedance at the second and low impedance at the third harmonic to the PA. The PA uses a packaged Silicon LDMOS...