Neutral Conductor Research Articles

LABORATORY PLATFORM FOR DEMONSTRATING THE SYMMETRICAL COMPONENTS ȚUGULEA POWER THEORY APPLIED ON GRID MODELS WITH NEUTRAL CONDUCTOR

In the context of the ever-increasing complexity of modern power systems, optimizing consumers’ performance to improve electrical energy quality becomes paramount. This article thoroughly examines the power transfer effects in the context of distorting and non-symmetrical regimes in three-phase, four-wire power systems, focusing on heavily nonlinear and unbalanced consumer influence across the grid. Particular emphasis is placed on the impact of these regimes on the parasitic active and reactive powers affecting linear and balanced consumers due to distorting and unbalanced ones. An essential aspect of this analysis is including the neutral conductor in the experimental circuit, enhancing relevance and a more profound understanding of consumer interactions in modern networks. Quantitative aspects of the phenomena involved are assessed from the perspective offered by SCPT (introduced by Andrei Ţugulea), allowing us to identify the source of non-symmetry and residual powers through comprehensive power balance equations for the active and reactive powers.

Power Quality Analysis of Electrical Installation at Commercial Center

For many years, power quality analysis has constantly been carried out at the power stations or sub-stations using the data collected at the data Centre of the power plant. However, this practice has proven to be erroneous and tedious to determine the exactly power quality problem especially when it comes to commercial facilities. Therefore, a revised approach of analysis for the power quality problems at the sites where they occur has been used in this research. This is because of the sensitivity of modern electronic equipment used in commercial facilities and also the need for accuracy of the data measurements carried out at the sites henceforth, with accurate data measurement, we can easily identify the power quality issues. Through-out this research, load unbalance of 28% was found. The solution to load unbalance was to balance the loads to 3,3% among the three phases and power losses caused by this unbalance current were calculated. Although the neutral conductor remained unchanged, harmonics especially triplen-harmonics was found to be more 10% recommended by IEC standards, therefore active harmonic filter of 200A was installed at the main panel board to reduce the losses caused by harmonics at the facility.

Experimental study and techno-economic evaluation of an active fault detection kit in the prospect of future zero energy building installations

This article presents an active fault detection kit, applicable to low voltage single-phase electrical installations, in the prospect of the Zero Energy Building concept, integrating on-site renewable energy generation and energy storage. This simple, flexible, self-powered and compact kit is capable of detecting faults, such as power theft (meter tampering), unintentional islanding and neutral conductor loss. Its operation is based on harmonic voltage injection, in series with the electrical installation, through a low-power H-bridge inverter and a current transformer, along with the corresponding harmonic current measurement, to estimate the impedance and effectively detect faulty conditions; the fast and robust Goertzel algorithm is utilized. Moreover, it features IoT communication capabilities, employing the ESP32 microcontroller, to exchange data and information with the installation meters. The functionality and effective fault detection of the proposed device are validated, through experimental tests on a custom-developed hardware prototype; IoT connectivity and data uploading are experimentally tested and verified, too. Finally, a sustainability assessment study is performed, using the Life Cycle Cost Analysis tool.

Boron-bridged bis(tetrathiafulvalene) zwitterionic neutral radical conductors: substituent effects on intramolecular and intermolecular electronic interactions and physical properties

Abstract We have recently proposed a new molecular design for neutral radical molecular conductors, based on the chemical composition of D2X-type charge-transfer salts (D = π-electron donor molecule, X = monovalent anion). Namely, we connected two tetrathiafulvalene (TTF)-based π-electron skeletons having a charge of +0.5 via a boron anion B–, to obtain a purely organic zwitterionic neutral radical {[(PDT-TTF-Cat)2]+B–}• that shows unique electronic states and properties in the crystal due to the intramolecular and intermolecular interactions of the +0.5-charged π-skeletons. In order to further explore the structural and electronic features of this kind of zwitterionic neutral radical conductor, in this study, we have examined chemical modifications to {[(PDT-TTF-Cat)2]+B–}•. As a result, an analog molecule {[(BMT-TTF-Cat)2]+B–}•, in which propylenedithio (PDT) groups on the TTF terminals in {[(PDT-TTF-Cat)2]+B–}• are replaced by bis(methylthio) ones, was successfully synthesized as air-stable single crystals. Interestingly, this chemical modification causes intramolecular charge disproportionation between the two TTF-based π-skeletons (i.e. the monovalent cation radical TTF+• and the neutral TTF0) coupled to the modulation of the intermolecular distances and interactions between these π-skeletons, leading to electrical and magnetic properties significantly different from those of the crystal of {[(PDT-TTF-Cat)2]+B–}•.

Measure for intensity of electrostatic interaction between two disjoint sets of charged conductors

Measure for intensity of electrostatic interaction between two disjoint sets of charged conductors is introduced, and it is called relative intensity of interaction (RII). Firstly, we examine properties and we found various forms and upper bounds for RII between charged conductors and neutral conductors. The most important derived expression for RII is in terms of Schur complement of original capacitance matrix and capacitance matrix of system without neutral conductors. RII between two disjoint sets S1 and S2 of arbitrarily charged conductors is bounded above by sum of RII’s between charged set S1 and neutral set S2, and vice versa.

On fire risk reduction when operating individual households

The article aims to elaborate a technical means for reducing fire occurrence in internal electrical networks of individual households. General scientific methods of numerical analysis, electric circuit theory, and prediction theory were used. It was determined that the operating mode of the electric network under study is characterized by a significant unbalanced power consumption due to the asymmetry and non-sinusoidality of phase currents caused by the occurrence of additional symmetrical components of forward, reverse, and zero sequences. Additional heat losses increase significantly and lead to overheating of the neutral conductor, thus intensifying fire risks. On the basis of measurements and the authors’ software, a simulation modeling of integration of the developed balancing device into the investigated network was carried out. The conducted analysis found that the developed device can reduce additional heat losses and fire risks by over 90%. Using statistical methods of forecasting, regression analysis in particular, a preventive long-term assessment of the level of additional power losses was conducted. Autoregressive equations for predicting the parameter of additional power losses at a certain probability level were derived. MATLAB graphic editor technologies and Excel software were used to visualize changes in the studied indicators. The results can be used by construction companies when designing the internal electrical network of individual households, as well as for researchers developing approaches to reducing additional losses of electrical energy.

A neural network-based classifier for identifying and locating neutral wire breaks in low voltage distribution networks

The breakage of the neutral conductor in low voltage distribution networks is a major concern for distribution companies. This breakage causes significant voltage deviations that can damage the connected equipment as well as jeopardizing people. The detection and localization of the breakage is a major challenge as it does not always manifest in the same way. This work presents a methodology based on artificial intelligence for the detection and localization of neutral conductor breaks in distribution networks. Two neural networks are trained in attempt to solve each of the challenges. For this purpose, measurements commonly taken by smartmeters such as power and nodal voltages are used. The methodology is evaluated in simulation exhibiting a good performance.

Evaluasi Ketidakseimbangan Beban Pada Penyulang Unicora

Load imbalance in electrical distribution transformers can lead to significant power losses and decreased efficiency in electrical distribution systems. This study focuses on the load imbalance problem at the Unicora feeder of PT PLN (Persero) ULP Singosari, which hinders optimal operational efficiency. The purpose of this research is to evaluate the extent of load imbalance, its impact on power losses, and the effectiveness of load balancing interventions in mitigating these losses. The methodology includes phase load measurements from February to September 2021, analysis of load imbalance, and power loss simulations using ETAP 12.6.0 software. The study's important findings indicate that the average load imbalance decreased from 34% to 21% after implementing load balancing interventions. Concurrently, power losses in the neutral conductor were reduced from 106.3 kW to 78.0 kW. ETAP simulations revealed a total power loss of 773.5 kW in the Unicora feeder, underscoring the significant impact of load imbalance on system efficiency. The implications of this research are crucial for operational practices at PT PLN (Persero) ULP Singosari. The findings demonstrate that effective load balancing can significantly enhance distribution efficiency, reduce operational costs, and improve the reliability of electricity provision. This study advocates for continuous monitoring and adaptive management of load distribution in electrical networks to maintain optimal performance and sustainability.

SISTEM KETIDAK SEIMBANGAN BEBAN PADA JARINGAN TEGANGAN RENDAH MENGGUNAKAN ALAT PHB – SR ( PERALATAN HUBUNG BAGI SAMBUNGAN RUMAH) DI PT. PLN PERSERO ULP BINJAI TIMUR

Load imbalance in an electric power distribution system often occurs in the field. This is a single-phase load on Low Voltage Network customers that is not the same due to the large number of additional electrical loads that do not pay attention to system load imbalances. As a result of this imbalance, a current appears in the transformer neutral. The current flowing in the neutral of the transformer causes losses, namely losses due to neutral current in the neutral conductor of the transformer and losses due to neutral current flowing to the ground. By realizing PHB SR (Home Connection Equipment) is able to balance the load on the Low Voltage Network. balance the load on the Low Voltage Network periodically and continuously so as to reduce technical shrinkage (losses), simplify the Connection Field in the technical connection of the Low Voltage Network. Connection in the technical connection of the House Connection (SR) on the pole, improve the aesthetics and neatness of the Network System.

Analysis of Load Imbalance in Tarakan Distribution Transformer of PT PLN (Persero) Sukarami Customer Service Unit

Load imbalance in an electric power distribution system always occurs and the cause of this imbalance is unbalanced single-phase loads on low voltage network customers. As a result of this load imbalance, a current arises in the neutral of the transformer, which can cause power losses. The aim of the research is to analyse the load imbalance of the Distribution Transformer PC0044, PC0074, PC0088, PC0129, PC1319 on the Tarakan Feeder of PT PLN (Persero) Sukarami Customer Service Unit. The results of the research show that the highest peak load percentage occurs on the PC1319 Distribution Transformer, namely 93.0874%, and based on PLN ED Decree No. 0017.E/DIR/2014, transformer loading. The largest percentage of load imbalance occurs in the PC0044 Distribution Transformer, namely 38.0952%, and based on PLN ED Decree No. 0017.E/DIR/2014, the current imbalance between phases is included in the bad category because the load imbalance is ≥ 25%. The largest percentage of power losses due to neutral current in the transformer neutral conductor occurs in the PC0044 Distribution Transformer, namely 2.6737%, and based on PLN ED Decree No. 0017.E/DIR/2014, the neutral current TR is included in the good category because the power losses due to the neutral current in the transformer neutral conductor are <10%. The largest percentage of power losses due to neutral current flowing to the ground occurs in the PC0044 Distribution Transformer, namely 5.0784%.

Assessing High-Voltage Shore Connection Safety: An In-Depth Study of Grounding Practices in Shore Power Systems

There is growing concern regarding air pollutants (NOx, SOx, and PM) and carbon emissions from ocean-going vessels in harbor areas and the role of high-voltage shore connection (HVSC) systems in mitigating these emissions during vessel berthing. The HVSC operates as a TN grounding system in humid environments, and it needs a proper grounding design to ensure safety when faults occur. This article intends to examine the overvoltage resulting from fault currents and its implications for the safety of operators when a single line-to-ground fault takes place within the design of HVSC grounding systems. The assessment is carried out by employing actual scenarios and parameters from a container berth at Kaohsiung Harbor in Taiwan. Considering site conditions, such as the wet ground surface, human body resistance, and electric shock duration, the tolerable safe voltage level is derived using IEEE Std. 80 and IEC 60479-1. Based on the shore power system grounding architecture specified in IEEE/IEC 80005-1, an equivalent circuit model is constructed to calculate the fault currents using symmetrical component analysis. The actual touch voltages generated in various locations are analyzed under scenarios of connecting or disconnecting the equipotential bonding between the ship and the shore using neutral grounding resistor (NGR) designs. This article delves into the scenarios of electric shock that may occur during the operation of an actual container ship’s shore power system. It evaluates whether various contact voltage values exceed current international standards and verifies the grounding design and safety voltage specifications of IEEE/IEC 80005-1. According to the results of this study, the use of NGR and protective earthed neutral (PEN) conductors in HVSC is crucial. This can limit fault currents, reduce touch voltage, and ensure the safety of personnel and equipment. Therefore, ensuring and monitoring equipment conductors and adopting NGRs of appropriate sizes are crucial elements in maintaining electrical safety in HVSC systems.

Neutral Currents in Large Public Lighting Networks

The modern large public lighting networks are characterized by two major aspects that rise problems from both power quality and neutral current point of view in low voltage wye-connected three-phase electrical systems: (i) the supply system is unbalanced loaded; (ii) the presence of discharge sources. It is important to underline that nowadays,these aspects are not taken into account in the proper sizing of neutral conductors. The paper presents a simplified but enough accurate methodology to estimate the RMS value of neutral currents in lighting networks. The theoretical relationships are illustrated for a three-phase public lighting network that contains high pressure sodium lamps.

Analysis of Losses Due to Load Unbalance in a 2000 kVA Transformer at Supermall Mansion 2 Tower Tanglin Surabaya

The load unbalance causes a neutral current, the current flowing in the neutral conductor will cause an increase in losses in the transformer. The greater the losses incurred, the efficiency and reliability of the transformer will decrease. Based on this, a study was conducted on analyzing the losses on distribution transformers at Supermall Mansion 2 Tower Tanglin which aims to determine the percentage value of transformer loading, the value of transformer imbalance, the value of transformer losses, and the value of transformer efficiency. This is done so that the value of the installed transformer does not exceed the applicable SPLN value. During the measurement, it was found that the percentage value of the transformer loading was 38.88% during the daytime and 48.89% at night (maximum SPLN 80%, minimum 40%). The load unbalance value is 11.66% during the daytime and 10.33% at night (SPLN is categorized as good if < 10%). Copper losses (Pcu) are 91.3 kW during the daytime and 94.2 kW at night. The value of losses due to neutral currents is 0.134 kW with a percentage of 0.0071% during the daytime and 0.173 kW with a percentage of 0.0090% at night. The percentage of the current value in the neutral conductor is 26.36% during the day and 24.04% at night (SPLN is categorized as good if < 20%).

Passive filters allocation in unbalanced distribution network with high penetration of distributed generation

The purpose of this paper is the allocation of passive filters in an unbalanced power network with high penetration of distributed generation to minimize the costs of power losses in the distribution lines, including power losses caused by harmonic components and neutral conductor power losses due to unbalanced loads. The harmonic components and the fundamental current generated by the distributed generation cause a voltage increase in the generation bus, and the voltages in the network above the limit allowed by standard are reduced by allocating passive filters without cutting the active power in the distributed generation. The unbalance and reactive power compensation is performed by the ideal compensation method applied to the distribution network. The tests are for the IEEE 34 bus network, with the fourth wire in the simulation being the isolated neutral. The scatter search metaheuristic applied in the simulation tends to minimize the costs of power losses in the lines and the costs of the passive filters allocated in the medium voltage distribution network, meeting the operational constraints of the network.

Nonlinear Loads in Lighting Installations—Problems and Threats

Distorted currents drawn by nonlinear loads used in power installations (including lighting) can cause many problems. With the constantly progressing increase in the number of these loads, these phenomena can accumulate, constituting significant causes of serious failures in both electrical and electronic devices, as well as installation components. The effects of disturbances introduced to the network by nonlinear loads may include, for example, line overloads, overheating of transformers and motors, capacitor failures, accelerated degradation of insulation, etc. The article presents examples of measurement results for luminaires with discharge and LED sources. Measurements of the electrical parameters of a three-phase outdoor lighting installation consisting of luminaires with low-power LED sources and luminaires with discharge sources are also discussed. Based on the recorded waveforms, the measurement results were determined. High harmonic values for the phase currents and the current in the neutral conductor were recorded. The results of measurements of the parameters of LED luminaires with control systems, the operation of which causes excessive heat generation, are presented. The methodology for cable selection in circuits with current harmonics is described.

MAXIMUM ACTIVE POWER TRANSMISSION EFFICIENCY AND POWER FACTOR DEFINITION IN HYBRID SYSTEMS WITH ARBITRARY WAVEFORMS

Based on a theorem giving the maximum available active power with constant transmission losses valid for arbitrary waveforms it is possible rigorously generalize the definitions of power factor based on the definition of apparent power as the maximum power available. Then it could be applied to systems with non-symmetric, non-sinusoidal, and eventually time-varying (ie non-periodic) waveforms or DC grids. By this way, the application may be extended to hybrid multi-wire systems with asymmetrical phases, with different voltages, frequencies or waveforms (i.e. non-sinusoidal waves, such as rectangular or PWM) and even DC, which can be combined eventually sharing the neutral conductor.

Analisis Ketidakseimbangan Beban Pada Tranformator Distribusi Di Gardu Induk Budurn

Electricity is a basic need for humans today, it has been proven that humans are very dependent on electricity for their daily activities. If electricity is not available, then human daily activities will be disrupted. The occurrence of load imbalance that occurs in the R, S, and T phases due to the absence of concurrent when the load is turned on, resulting in a neutral current flow on the secondary side of the transformer. with the development of electric power distribution systems. The benefit of reducing losses on the neutral conductor of the distribution transformer is that it can produce savings in the supply of electricity, and other benefits obtained include the resulting system. The method used is that the data resulting from field measurements are converted into mathematical equations. From the research conducted, the results showed the average value of the loading current and load imbalance in the distribution transformer at the Buduran Substation, namely the average loading current of (14.4 A), Load Imbalance of (28.3 A), Neutral Current Losses of (2.34 W). And Copper Losses of (0.510945 kW).

ANALISA RUGI-RUGI DAYA (LOSSES POWER) PADA JARINGAN TEGANGAN RENDAH PT. MUSIMAS BATAM

PT. MUSIMMAS BATAM is one of the largest integrated palm oil companies in the world that requires a three-phase voltage supply of approximately 250 amperes for each phase. PT. Musimmas Batam is supplied from a 150,000 KVA transformer through the LVMDP Panel, with priority on supplying electricity needs. The 3-phase voltage values are obtained, namely: R-S = 404.4 V, R-T = 404.2 V, S-T = 404.1 V with a neutral voltage of R-N = 23.2 V, S-N = 23.1, T-N = 23.3. And the 3-phase current IR = 202.9 Amperes, IS = 213.7 Amperes, IT = 200.7 Amperes. Total Power Calculation at LVMDP based on the equation looking for Iaverage = 205.7 A, Based on the equation looking for Vaverage = 1212.7 V, Based on the equation looking for P = 241.9 Kw. Power losses for a 400 mm² wire (R = 0.047 Ω/km) is 46.6 watts/km = 0.046 kW/km, and the total length of the conductor cable from the LVMDP Panel to the Load 500 M with the calculation of power losses, namely : P = 4833 watts/km. While the total power supply is 8.0 Kw = 8000 watts, so it can be seen = 3167 watts/km (3.16 Kw). Where is the active power of the transformer (P) = 145.5 kW. Thus, the percentage of losses due to neutral currents in the neutral conductor of the transformer is 0.03%.Key word : LVMDP Panels, Cables, Loads

Consensus based phase connectivity identification for distribution network with limited observability

The mitigation of distribution network (DN) unbalance and the use of single-phase flexibility for congestion mitigation requires accurate phase connection information, which is often not available. For a large DN, the naïve phase identification proposed in the majority of the prior works using a single voltage reference, this does not scale well for a multi-feeder DN. We present a consensus algorithm-based phase identification mechanism which uses multiple three-phase reference points to improve the prediction of phases. Due to the absence of real measurements for a real-suburban German DN, the algorithms are developed and evaluated over synthetic data using a digital twin. To utilize strongly correlated measurements, the DN is clustered into zones. We observe those reference measurements located in the same zone as the single-phase consumer, with unknown phase connectivity, leads to accurate prediction of DN phases. Four consensus algorithms are developed and compared. Using numerical results, we recommend the most robust phase identification mechanism. In our evaluation, measurement error, and the impact of the neutral conductor are also assessed. We assume limited DN observability and apply our findings to a German DN without smart meters, but only less than 8% of nodes have measurement boxes along with single-phase consumers with a home energy management system. Voltage time series for 1 month (hourly sampled) is utilized. The numerical results indicate that for 1% accuracy class measurement, the phase connectivity of 308 out of 313 single-phase consumers in a German DN can be identified. Further, we also propose metrics quantifying the goodness of the phase identification. The phase identification framework based on consensus algorithms for DN zones is scalable for large DN and robust towards measurement errors as the estimation is not dependent on a single measurement point.

Ensuring the Serviceability of 0.4 kV Electric Networks in Case of Breaks of the Combined Neutral and Earth Conductor

Breaks of the neutral conductor are among the most common failures in 0.4 kV networks. At present, to ensure the electrical safety of personnel, grounding loops with standard values of grounding resistance in compliance with Electrical Installation Code (PUE) are set up. Such grounding loops do not have any significant impact on the power quality indicators. Moreover, their construction is quite expensive and requires significant material costs. To maintain power quality parameters within the permissible limits, grounding loops with much lower resistance values are needed, which, however, are much more expensive. One of the ways for solving the problem under consideration is the use of natural grounding conductors for temporarily maintaining the standard electric power quality. The article addresses the problem of ensuring the electric power quality in case of breaks of the neutral conductor and a decrease of its conductance with reference to voltage unbalance. The ways of solving this problem are briefly outlined, in particular, by laying an additional conductor or using the TN-C-S grounding system. One of the alternative solutions to the problem considered is the use of natural grounding conductors, for example, a reinforced concrete foundation or a metal fence. The grounding resistances of such grounding conductors were calculated, the estimated values of which have confirmed the possibility of using them to comply with the PUE requirements. Practical recommendations for implementing the suggested proposals are given. One of them is to develop a device for monitoring the state of the neutral protective and main conductors. The key related issue of the problem considered is to ensure the electrical safety of both personnel and all people staying in the territory in which the grounding is temporarily used as the main neutral conductor. This issue will be addressed in the subsequent publications.