V. S. Larin

Bio: V. S. Larin is an academic researcher from Unitary enterprise. The author has contributed to research in topics: Transformer & Overvoltage. The author has an hindex of 3, co-authored 6 publications receiving 13 citations.

Resonance Overvoltages in Primary Winding of a Station Service Voltage Transformer

Abstract: The design of new types of transformer equipment, in particular, station service voltage transformers (SSVTs), requires a detailed consideration of all technical aspects and conditions of their application and their design features. One problem is to provide their resistance to effects associated with their interaction with the grid. During transient events in the network caused by the operation of switching equipment or short circuits, the transformers are affected by the oscillating voltage, which, under certain conditions, can cause resonance overvoltages inside their windings. The design of SSVTs differs from that of common power transformers, mostly because different types of windings are used, which determines the essential difference in the natural oscillation frequencies and the theoretical possibility of the development of resonance overvoltages under changed combinations of network parameters and switching conditions. In this paper, the problems of estimating the natural and dominating oscillation frequencies in SSVT windings and the voltages on the longitudinal insulation of SSVT windings under the resonance conditions are considered. The proposed approach is applicable not only to SSVTs, but also to other types of transformer equipment.

Studying the Impulse Overloads in the Windings of a Station Service Voltage Transformer

Abstract: One of the key factors determining the performance of a 110–500-kV station service voltage transformer (SSVT) is a compact insulation design that provides minimum winding sizes. Since SSVTs are new equipment that combine the operational features of a power transformer and the design features of a measuring voltage transformer, it is necessary to study the characteristic transient processes occurring under the impact of lightning-impulse test voltages and lightning and switching overloads in operation in order to ensure proper insulation design. The article presents the results of an experimental investigation of impulse transients in the windings of a full-scale mockup model of an active part of a 20-kV A SSVT with a rated voltage of 110 kV. The influence of grounding the low-voltage winding terminals on the maximum values and duration of impulse stresses on the longitudinal insulation of the high-voltage winding is revealed. It is shown that, unlike in the case of power transformers with disc windings, more significant effects on the insulation are produced when no load is applied on the low-voltage windings.

A Study of Transferred Overvoltages on the Secondary Windings of Station Service Voltage Transformers

Abstract: Station service voltage transformers (SSVTs) are finding increasingly wide application in world practice. One of the key issues of ensuring the reliable operation of the SSVTs is the coordination of their insulation and the protection against high-frequency overvoltage including that induced on the secondary windings. The paper presents the results of measuring the transfer functions and the oscillographic recording of the voltages on the SSVT secondary windings. The transferred overvoltage ratios of unloaded and loaded transformer secondary windings are estimated. Estimated rates of output-voltage increase at resonant frequencies are presented. The transferred overvoltage ratios on the SSVT primary windings under the impact of the damped oscillatory voltage are assessed.

Transferred overvoltage on nonloaded transformer windings: Evaluation of voltage and protective measures

Abstract: This paper reviews the main mechanisms of voltage transfer between transformer windings and theoretical determination of transferred overvoltage magnitudes. The approaches for experimental determination of transferred overvoltage magnitudes are stated, and practical examples of application of these approaches are presented. Recommendations of actual normative documents on protection from transferred overvoltages caused by fast transient overvoltages are described. Measures of protection from resonance transferred overvoltages caused by the effect of oscillatory voltages are proposed.

A Broadband Model of Step-up Transformers for High-Frequency Power-Supply Units of Electrostatic Precipitators

Abstract: Compared to conventional technologies based on low-frequency thyristor-controlled power-supply units, the high-frequency power-supply units of electrostatic precipitators, based on a new cutting-edge technology, ensure more efficient gas conditioning at thermal power plants and industrial enterprises. Particular attention in the design of high-frequency power-supply units should be paid to designing a step-up transformer with high nominal output voltage and capacity at an operational frequency from several to tens of kilohertz. The design features of this transformer significantly influence the characteristics of the whole high-frequency power-supply unit. This article proposes an approach to forming a broadband design transformer model which correctly works in a broad range of low and high frequencies. This model allows imitating processes in the transformer together with an external circuit; in this case, it is possible to analyze the influence of the transformer design on the characteristics of the whole unit, as well as the operating conditions of the transformer itself, which is especially important in the device design phase.

Resonance Overvoltages in Primary Winding of a Station Service Voltage Transformer

Abstract: The design of new types of transformer equipment, in particular, station service voltage transformers (SSVTs), requires a detailed consideration of all technical aspects and conditions of their application and their design features. One problem is to provide their resistance to effects associated with their interaction with the grid. During transient events in the network caused by the operation of switching equipment or short circuits, the transformers are affected by the oscillating voltage, which, under certain conditions, can cause resonance overvoltages inside their windings. The design of SSVTs differs from that of common power transformers, mostly because different types of windings are used, which determines the essential difference in the natural oscillation frequencies and the theoretical possibility of the development of resonance overvoltages under changed combinations of network parameters and switching conditions. In this paper, the problems of estimating the natural and dominating oscillation frequencies in SSVT windings and the voltages on the longitudinal insulation of SSVT windings under the resonance conditions are considered. The proposed approach is applicable not only to SSVTs, but also to other types of transformer equipment.

Research On Ferromagnetic Resonance Overvoltage Based On Station Service Voltage Transformers

Abstract: Station Service Voltage Transformers (SSVT) combines the operating characteristics of power transformers and the design characteristics of measuring voltage transformers. Due to its lower initial cost and higher power supply reliability, its applications have been extended beyond that of auxiliary power. During transient events in the network caused by the operation of switching equipment or short circuits, the transformers are affected by the oscillating voltage, which, under certain conditions, can cause resonance overvoltage inside their windings. Based on the ATP-EMTP platform, the ferromagnetic resonance of SSVT is simulated and its simulation model, simulation algorithm, and waveform are analyzed. Based on the simulation analysis results, this paper puts forward the preventive measures of transformer ferromagnetic resonance from the perspective of voltage harmonics and insulation coordination.

A Study of Transferred Overvoltages on the Secondary Windings of Station Service Voltage Transformers

Abstract: Station service voltage transformers (SSVTs) are finding increasingly wide application in world practice. One of the key issues of ensuring the reliable operation of the SSVTs is the coordination of their insulation and the protection against high-frequency overvoltage including that induced on the secondary windings. The paper presents the results of measuring the transfer functions and the oscillographic recording of the voltages on the SSVT secondary windings. The transferred overvoltage ratios of unloaded and loaded transformer secondary windings are estimated. Estimated rates of output-voltage increase at resonant frequencies are presented. The transferred overvoltage ratios on the SSVT primary windings under the impact of the damped oscillatory voltage are assessed.

Overview of Voltage Transformers Suitable for High Voltage Levels

Abstract: With the development of the power grid, high voltage transmission lines and smart substations are put into use This requires higher-performance voltage transformers Potential transformer(PT) can no longer meet the measurement needs Analysis of the voltage measurement requirements in the power grid, pointing out the limitations of traditional PT such as poor insulation performance and ferromagnetic resonance The principles, characteristics and application of three new voltage transformers, that is, resistance voltage transformer, capacitor voltage transformer(CVT), and optical voltage transducer(OVT) are described, and the practical problems of new voltage transformers are summarized and put forward