The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
This paper presents findings from a finite element modelling based simulation study conducted to understand the moisture and temperature dependency of power transformer winding clamping pressure. Set of laboratory experiments were used to measure moisture dependent mechanical properties of high-density pressboard. First, 400 kVA disc type transformer winding was simulated to separately study the effects...
This paper presents a multi-source data and information fusion framework for power transformer condition assessment. The proposed method adopts Bayesian Network (BN), which can integrate every piece of data and information obtained from different transformer diagnostic measurements. Within the Bayesian Network, Monte Carlo and Bootstrap methods are employed to extract the most informative characteristics...
This paper studies the Australian market conditions and subsidies in place to promote the growth of wind power through the use of a stochastic linear programming model. This model optimizes the profit obtained for a static investment based on a variety of wind and price scenarios. It is subject to different constraints which focus on the amount of initial capital injected by an investor, selling power...
A novel algorithm for transformer hot spot temperature prediction is proposed and presented in this paper. The algorithm is an integration of Support Vector Regression (SVR) and Information Granulation (IG), which is based on the principle of time series regression. The historical records consisting of measured hot spot temperature, top oil temperature, load current and ambient temperature of a transformer...
The interest for installation of solar Photovoltaic (PV) systems in the distribution network has been increasing due to their declining cost and high electricity price from the utilities. On the downside, the PV power generation is sensitive to the variation in solar irradiation, which can cause potential challenges in the low voltage network in terms of voltage quality and management. In this research,...
Wavelet transform-based Partial discharge (PD) signal extraction methods have been widely adopted in the past ten years. However, these methods may still encounter some difficulties in online PD measurements, in which PD signals can be overwhelmed by noise. To overcome the limitations of wavelet transform-based methods, the authors of this paper have developed two novel signal extraction methods....
Partial discharge (PD) measurement has been widely adopted for condition assessment of transformers. The major tasks include effective extraction of PD signals from measured signals, accurate representation of PD signals, explicit multiple PD source separation, and PD source classification. This paper applies empirical mode decomposition (EMD) and mathematical morphology (MM) for extracting PD signals...
In this paper, a statistical approach for evaluating the transformer's paper insulation is proposed. The proposed approach adopts multi-variable analysis to investigate the correlations between the degree of polymerization (DP) of paper insulation and increase rates of different dissolved gases in oil. Moisture in paper, oxygen and temperature are important factors influencing paper insulation degradation...
Rooftop Solar Photovoltaic (PV) systems installations have been increasing in the Low voltage distribution networks due to decreased cost and government incentives (e.g. feed-in-tariff). The high penetration of these PV systems can inject harmonics into the network causing problems to sensitive loads and controllers of loads. Due to the solar irradiation dependency, the power generation is variable...
Demand for alternative insulating liquids for power transformers are increasing due to the safety and environment concerns. Ester based insulating liquid is considered as a potential alternative for mineral oil since it is highly biodegradable and has high fire point. On the other hand, Polarization and Depolarization Current (PDC) measurement technique has been widely used to evaluate moisture and...
Gas-insulated switchgears (GIS) are emerging as more capable power system assets than conventional air-insulated switchgears (AIS), especially in terms of operational reliability and maintenance requirements. However, insufficient consideration is often given to comparing GIS and AIS substation project options. Therefore, a more effective approach is needed to better inform project investment decisions...
In this paper a time domain diffusion-driven model is presented to investigate the correlation between the distribution of moisture during thermal transients, and the resultant polarization and depolarization current (PDC) measurement, for transformer cellulosic insulation. The oil-impregnated cellulosic insulation is modeled as being multiple layers of paper, with each layer having a different permittivity...
Efforts have been underway to estimate the life remaining of the paper insulation used in power transformers, and thus estimate the remaining life of the whole unit. However, one problem encountered when estimating remaining life is that the current state of the paper is not often exactly known. One method to determine the condition of paper is to measure the furan content of the oil to estimate the...
With increased power demand and the complexity of power systems, the Australian electricity market needs to undertake a series of changes and updates, including power system deregulation, allowing independent power producers (IPPs) to enter the market. One of the current systems that needs to be updated is the spot pricing system, which involves the application of slack bus independent distribution...
Future distribution networks in Australia are likely to include large volume of medium scale concentrated solar power (CSP) plants. Like other renewable resources such as photovoltaic (PV) and wind, CSP has a variable output. To plan the power system's reserves with variable generator like CSP, it is important to study the long term energy yield in detail. Moreover, the long term energy yield is the...
This paper proposes a diffusion-driven dielectric response model, which aims to reveal the effect of moisture diffusion on the dielectric response measurement of transformer insulation. In the proposed diffusion-driven model, the oil-impregnated pressboards are modeled as multiple layers and it is assumed moisture diffuses from one side of the pressboard. Then the dependency between the moisture concentration...
Continuous Partial discharge (PD) monitoring can help assess the integrity of transformer insulation system. Over the past few decades, various aspects of PD techniques have been investigated. Current research of PD focuses on multiple PD sources classification, which aims to identify the types of several defects that may coexist in a transformer and cause discharge. This paper develops a hybrid discrete...
This paper presents a detailed analysis for determining the impact of adding single phase photovoltaic (PV) systems in residential power distribution networks. This study highlights the issues arising due to the increase in fault levels in the network caused by the contribution from PV generators. A typical power distribution network for a suburban area has been modeled in PSCAD and the changes in...
Corrosion of the pin of high voltage porcelain and glass cap-and-pin insulators, which is mainly caused by leakage currents, can severely compromise the mechanical integrity of the insulator, leading to a shorter service life. This paper investigates the potential for room temperature vulcanising silicone (RTV) coatings on high voltage insulators in Queensland. These silicone coatings are designed...
This paper describes a load shedding methodology for use in time sequential market simulations of zonal network models, where each zone represents a larger region. Intra-regional network limitations can be modelled using constraint formulations. However, when using regional load traces, any load shedding due to constraints violating causes regional unserved energy only. This paper presents a methodology...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.