Operation Of Distribution Transformer Research Articles

PENYEIMBANGAN BEBAN TRANSFORMATOR DISTRIBUSI PCC-007 UNTUK MENGURANGI RUGI-RUGI JARINGAN PADA TEGANGAN MENENGAH 20KV

The distribution system of electrical power networks serves as a means to distribute electrical energy to both industrial and household consumers. With the increasing population growth, the number of electrical energy users or consumers also increases, potentially impacting the loading on each distribution transformer. If the loading on each transformer increases, it can lead to overload, load imbalance, power losses, and damage to the transformer. Therefore, to ensure the proper operation of distribution transformers, PLN (a state-owned electricity company in Indonesia) has set a standard for the loading on distribution transformers, which should not exceed 80%. This research aims to measure the loading on distribution transformers and analyze the occurrence of power losses caused by load imbalance. Measurements are conducted using a clamp meter and earth tester to obtain current and voltage values as well as the resistance value of grounding. Subsequently, calculations are performed for transformer loading, load imbalance, and power losses on the feeder.

Design of Reactive Power Online Monitoring System of Intelligent Distribution Transformer Based on Edge Computing

Due to the unbalanced development of various regions, in most regions, the distribution transformer of medium voltage line has not realized automatic monitoring, so the staff cannot monitor it in real-time. Therefore, an online monitoring system for the reactive power status of intelligent distribution transformers based on edge computing is designed. The system hardware structure configuration consisting of the master station layer, the edge layer and the acquisition layer is constructed, and the system software functional structure consisting of data processing, online monitoring, and system management is designed. On this basis, the continuous sampling data of the reactive power of the intelligent distribution transformer is collected, and based on edge computing, the reactive power operation characteristics of the intelligent distribution transformer are obtained and matched to judge the reactive state of the intelligent distribution transformer operation, so as to realize online monitoring of the reactive state of the intelligent distribution transformer. The experimental results show that the online monitoring accuracy and efficiency of the intelligent distribution transformer reactive state are high.

Fault diagnosis of electric transformers based on infrared image processing and semi-supervised learning

It is crucial to maintain the safe and stable operation of distribution transformers, which constitute a key part of power systems. In the event of transformer failure, the fault type must be diagnosed in a timely and accurate manner. To this end, a transformer fault diagnosis method based on infrared image processing and semi-supervised learning is proposed herein. First, we perform feature extraction on the collected infrared-image data to extract temperature, texture, and shape features as the model reference vectors. Then, a generative adversarial network (GAN) is constructed to generate synthetic samples for the minority subset of labelled samples. The proposed method can learn information from unlabeled sample data, unlike conventional supervised learning methods. Subsequently, a semi-supervised graph model is trained on the entire dataset, i.e., both labeled and unlabeled data. Finally, we test the proposed model on an actual dataset collected from a Chinese electricity provider. The experimental results show that the use of feature extraction, sample generation, and semi-supervised learning model can improve the accuracy of transformer fault classification. This verifies the effectiveness of the proposed method.

Research on Loss Reduction and Energy Saving Operation of Distribution Transformer and Line below 10kV

Research on Loss Reduction and Energy Saving Operation of Distribution Transformer and Line below 10kV

Transformers Improvement and Environment Conservation by Using Synthetic Esters in Egypt

Distribution transformer (DT) is a crucial component in power systems as it exchanges energies between different voltage levels or between utility grid and DC microgrids. Nevertheless, the operation of an oil-immersed DT is limited by the thermal and electrical capabilities of the internal insulating liquid. This paper aims to raise the efficiency of distribution transformers and preserve the environment by using a biodegradable insulating liquid instead of the conventional mineral insulating oil (MIO). This work examines the Egyptian case, where a real distribution network located in middle Egypt is selected as a pilot project. Study and analysis of the status que of the insulation system inside DTs are done with the aid of fault-tree analysis. The deficiency of the insulation system is confirmed by conducting an electronic survey of 100 expert participants. The most appropriate solution among three different alternatives is confirmed using the weighting and ranking method. The best choice suitable for the selected area is the substitution of MIO by synthetic ester (SE). The technical and environmental advantages achieved by the presented solution are discussed. The feasibility studies have proven that the solution is positively acceptable in all aspects. An execution plan is established for the application of proposed solution on the selected Egyptian distribution network.

Configurations, Power Topologies and Applications of Hybrid Distribution Transformers

Distribution systems are under constant stress due to their highly variable operating conditions, which jeopardize distribution transformers and lines, degrading the end-user service. Due to transformer regulation, variable loads can generate voltage profiles out of the acceptable bands recommended by grid codes, affecting the quality of service. At the same time, nonlinear loads, such as diode bridge rectifiers without power factor correction systems, generate nonlinear currents that affect the distribution transformer operation, reducing its lifetime. Variable loads can be commonly found at domiciliary levels due to the random operation of home appliances, but recently also due to electric vehicle charging stations, where the distribution transformer can cyclically vary between no-load, rated and overrated load. Thus, the distribution transformer can not safely operate under highly-dynamic and stressful conditions, requiring the support of alternative systems. Among the existing solutions, hybrid transformers, which are composed of a conventional transformer and a power converter, are an interesting alternative to cope with several power quality problems. This article is a review of the available literature about hybrid distribution transformers.

Application of Markov Model for Determination of Average Lifetime of a Transformer Distribution System

Abstract The study presents an analysis of the operation process of elements of a system for electrical energy transformation in natural conditions of their usage. The research object is a system of HV and MV distribution transformer operation. The method of construction and an example of the Markov operation process have been presented for the analyzed technical objects. The model of the operation process was built on the basis of analysis of spatial states and events involved in operation of the analyzed technical objects. An average lifetime of the analyzed technical system was determined for assumptions accepted for a stochastic process which is a mathematical model of the distribution transformer operation process.

Maximum Utilization of Dynamic Rating Operated Distribution Transformer (DRoDT) with Battery Energy Storage System: Analysis on Impact from Battery Electric Vehicles Charging

This paper investigates thermal overloading, voltage dips and insulation failure across a distribution transformer (DT), under residential and battery electric vehicle (BEV) loadings. The objective of this paper is to discuss the charging impact of BEVs on voltage across consumer-service points, as well as across the life of paper insulation under varying ambient temperatures (during winter and summer), with and without a centralized battery energy storage system (BESS). This study contributes in two ways. The first part of this study deals with coordinated and uncoordinated BEV charging scenarios. The second part of this study deals with maximum utilization of a test DT rated under dynamic thermal rating (DRoDT). The DRoDT integration with BESS is carried out to flatten the load spikes, to obtain maximum DT utilization, to achieve active power and voltage supports in addition to an enhanced DT lifespan. The obtained results indicate that, when test DT operates under the proposed hybrid technique (combining both dynamic transformer ratings and a centralized BESS), it attains maximum utilization, lower hot-spot temperature, enhanced lifespan, less degraded paper insulation and an improved voltage across each consumer service point. The proposed technique is furthermore found effective in maintaining the loading across the distribution transformer within the nominal limits. However, under excess loading during peak hours, the proposed technique provides relief to the DT to a certain extent. To achieve an optimal DT operation and an enhanced BESS lifespan, the BESS is operated under nominal charging and discharging cyclic limits. Under the proposed DRoDT integration with BESS, DT attains 25.9% more life when loaded with coordinated BEV charging, in comparison to no BESS integration under the same loading scenario. The worst loading due to uncoordinated BEV charging also brings 51% increase in DT life when loaded under the proposed technique.

A transfer learning fault diagnosis model of distribution transformer considering multi‐factor situation evolution

Aiming at the problem of limited fault data and data expiration of distribution transformers, a transfer learning fault diagnosis model of the distribution transformer considering multi‐factor situation evolution is proposed in this paper. First, the state quantities that influence the distribution transformer operation are constructed, and fuzzy binary quantification is used for the state quantities. The association between the state quantities and the fault is explored by the fuzzy Apriori algorithm, and the key state variables that induce the transformer fault are extracted. The Tanimoto coefficient is introduced for the limited fault data of distribution transformers, and the effective auxiliary fault data is transferred to the target distribution transformer. On this basis, the fault diagnosis model based on information transfer is proposed. A health index is introduced to describe the distribution health levels, and the auxiliary fault data in different health levels is transferred because data has expired. On this basis, the fault diagnosis model for data expiration is proposed. The weights of the target and auxiliary fault data in the above model are iteratively solved by using the TrAdaBoost algorithm. Finally, an example analysis is carried on the basis of distribution transformer fault data, and the simulation results show that the fault diagnosis accuracy of the model is high and that it has stronger generalization ability than traditional diagnosis models. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Analysis and Research of Three-phase Unbalance in Distribution Transformers

The distribution transformer unbalanced operation status will affect the life of the transformer and increase the losses of the transformer besides a series of problems such as grid voltage drop, flicker, low power factor, line losses increase. This article analysis harm caused by the unbalanced operation of distribution transformers from the perspective of power quality and the measures dealing with three-phase unbalanced of distribution transformers.

Field-Based Evaluation of the Effects of Shunt Capacitors on the Operation of Distribution Transformers

This paper analyzes the effects of shunt capacitors installed on the low voltage sides of 10/0.4 kV distribution transformers on the operation of these transformers. Using the results of an extensive measurement campaign, this paper compares: real and reactive power losses, secondary-side current, and primary-side apparent power before and after the installation of transformer capacitors. The following four cases of reactive power compensation are considered and discussed: adequate, conditionally adequate, and total compensation, as well as overcompensation. The presented analysis helps to identify transformer substations where the initial compensation should be changed or adjusted, in order to improve transformers’ operational performance. Voltage dependencies of real and reactive power demands of the transformer-supplied loads are taken into account, based on the previously identified load characteristics in the considered networks as well as voltage dependence of reactive power of shunt capacitors. The result with and without including these voltage dependencies in the analysis is compared and discussed.

Innovative calculation method of inductive reactive compensation capacity based on optimum injection current

An innovative method based on optimal injection current is introduced to calculate reactive compensation capacity during unbalanced three-phase distribution transformer operation. This method offers a new process that governs the three-phase unbalanced distribution transformers compared with susceptance compensation and calculates the operation capacity of the reactive power compensation electric control equipment through reverse thinking. Compensation effect is further optimised by adding reasonable restrictive conditions and neglecting inductive compensation combined with practical electrical engineering computing. This study presents the calculation method of optimal injection current with pure capacitive reactive power control along with its basic principles, algorithm implementation, and practical analysis. Results show that calculation based on optimal injection current avoids the overcompensation and overcurrent of susceptance compensation while improving the governance of the unbalanced three-phase distribution transformer effect.

The New Development Trend of Distribution Transformer

Firstly, this paper introduces the development of new materials, new technology and new manufacture in power industry of China, energy-saving, low noise and smart distribution transformers are widely used in countryside power grid reconstruction. In this paper, application status and development trend of different types of distribution transformers were introduced and compared in terms of new material and new structure, such as oil-immersed distribution transformer, amorphous core transformer(AMT), dry-type transformer, SF6 insulated distribution transformer, composite transformer and other types of distribution transformers. The development of distribution transformer is mainly based on energy saving, miniaturization, wound core and amorphous alloy nowadays, but the class-H dry-type transformer and tridimensional toroidal-core amorphous alloy transformer are the future direction of development. The technology application of smart distribution grid, power electronics technology and dynamic reactive power compensation technique will also affect the safety and economic operation of distribution transformer.

A Control Device for Distribution Transformer Neutral Current and Loss

This paper develops a control device for distribution transformer neutral current and loss caused by unbalanced loads. Due to multi-objective optimization, its control strategy is designed, considering the reliable operation of distribution transformers and its performance. This device can gather power quality parameters, calculate the optimal regulation and control capacitor switching, which consists of power quality acquisition unit, central processing unit (CPU), capacitor control cabinet and power supply. After simulation and experiment, the result shows device can achieve target by dynamic adjustment.

Distribution Transformer's Insulation Thermal Coefficient Measurement under Unbalanced Operation

A reliable and endless supply of electricity is highly dependent on good operation of distribution transformers. A huge number of customers are directly supplied via any of the transformers. Loading of the transformers under unbalance conditions is an important factor that influences the life of their insulation. In this paper we will consider two typical 315 KVA, 20 kV distribution transformers with the same characteristics but under different operating conditions. Thermal coefficients and remnant life of two distribution transformers are measured and show a remarkable difference between thermal coefficients of two transformers.