Reducing of total harmonic distortion using passive filter simulation to suppress harmonic currents with the case: General Hospital, Universitas Kristen Indonesia Jakarta

With the increasing need for and use of electrical energy amid increasingly rapid technological advances, especially in the use of electronic equipment in hospitals, it is necessary to pay attention to the problem of harmonics due to the use of non-linear electrical equipment. Therefore, it is necessary to measure the current and voltage THD for each non-linear equipment user. If the current and voltage THD values do not meet the standards, then a filter design is carried out so that the THD values meet the standards. Based on the results of THD measurements on the Main Distribution Panel (MDP) of RSU UKI, it was found that the THD of the voltage varied between 0.7877% - 2.4363% and the current THD varied between 5.3073% - 9.2363%. The measured THD value refers to the IEEE 519-2014 standard. If the THD value of the measurement results exceeds the IEEE 519-2014 standard, a harmonic filter is needed. With the simulated single tuned filter design, the current THD decreases within the standard value. The THD value of the current after installing the filter at the three MDP’s of the RSU UKI, namely MDP A of 1.72%, MDP B of 0.64% and MDP C of 1.30%.

A survey of harmonics in power systems of ships with electrical propulsion drives

The number of commercial ships with electric propulsion is in continuous increase due to their versatility and fuel efficiency. Total harmonic distortion consequences on marine electrical power systems will be discussed. This paper aims to highlight the need for harmonic filter implementation on electric propulsion with static converters. For this study, a simulation in Matlab Simulink will reveal the effect of electrical filters on THD and voltage end current waveforms.

DESIGNING MICROWAVE BAND ATTENUATORS AS ELECTRIC FILTERS WITH LOSSES

This paper presents the results of modeling attenuators with an attenuation of 1,2 dB and 1,8 dB, based on a harmonic filter with resistive inserts. Resistive inserts were introduced into the low-resistance sections of the harmonic filter, and resistive loops were connected to the high-resistance sections of the filter. An implementation of a 10 dB attenuator based on a quasi-polynomial bandpass filter with losses is proposed. The working frequency band of such attenuators reaches 4 GHz.

Power Sharing and Control by Droop Controller with Advanced Filter Design: A Case Study in Lock-down Periods

In the lock-down period, the islanding mode of operation with droop controllers has several advantages in the alternating current grid. This study focuses on an improvised droop controller. It consists of an advanced filtering segment embedded with a conventional droop controller, which overcomes the drawback of droop controllers of the non-handling of non-linear loads in an ordinary situation. A selective harmonic elimination technique in grid-connected mode and lock-down mode and an advanced filter embedded with droop control are used so that the proposed controller can also work as an Active Harmonic Filter (AHF). The simulation results in different cases show that the proposed controller can control the active and reactive power in the lock-down period as well as the harmonics in the normal period up to an extent.

Harmonic Mitigation Using Passive Harmonic Filters: Case Study in a Steel Mill Power System

In this study, we mitigated the harmonic voltage in a power system that contained the roughing mill (RM) and finishing mill (FM) motor drives. AC/DC converter type RM drive is a non-linear, large-capacity varying load that adversely affects power quality, e.g., a flicker, voltage distortion, etc. The voltage drop can be compensated within a certain limit by using the proper capacity of a power capacitor bank. In addition, the voltage distortion can be controlled as per the guidelines of IEEE Std. 519 using the passive harmonic filter corresponding to the characteristic harmonics of the motor drive load. The passive harmonic filter can provide an economical solution by mitigating the harmonic distortion with a proper reactive power supply. However, at the planning level, attention should be paid to avoid system overvoltage that is caused by the leading power under light load conditions and also the problem of parallel resonance between the harmonic filter and the step-down transformer. In addition, when designing the filter reactor, the K-factor and peak voltage must be considered; the filter capacitor also requires a dielectric material that considers the harmonic peak voltage. The purpose of this study was to acquire a better understanding of the filter applications as well as verify the field measurement, analysis, and design of harmonic filters together with its performance.

Investigation into Class E/F3 with Parallel Network

The system of equations for processes in the amplifier output network is analytically formulated. This system of equations considers parameters of resonant networks at higher harmonics. To calculate amplifier output network, the system of five equations was built for five unknowns, to which the condition of positive second voltage derivative at extremum of drain voltage was added. Two equations correspond to class E conditions, another two — quadrature waveforms at load and at additional resonant network. The last equation is the condition of extremum at the point near middle of drain voltage pulse. This system was solved using computer algebra program. The circuit elements and waveforms were calculated using the derived parameters. By choosing different parameters, it is possible to obtain various amplifier realizations, which will demonstrate features of different class F variants. The obtained amplifier parameters drain voltage and current waveforms were verified with calculated ones using the harmonic balance simulating software. The variant, which is closer to class E/F3 mode, was chosen to build an experimental amplifier prototype on frequency 2MHz using IRF530 MOSFET as a switch. The prototype was tested in the range of supply dc voltage up to 24V with the output power greater than 6W, while the amplifier efficiency was >80%. In the experiment, the ratio of peak drain voltage to dc supply voltage was measured to be 3.3 at the duty ratio 50%, unlike class E amplifier, where this value is around 3.65, and on practice, considering non-linear drain to source capacitance, it may achieve 4. The experimental second harmonic level amounted to be -20 dB relatively to fundamental, and the third one — 28.5 dB, which is due to an additional second harmonic filter. The paper results are useful for introduction of such circuits to practice.