WELCOME

SOLID STATE TRANSFORMER

INTERFACED WIND ENERGY SYSTEM

PRESENTED BYAKHILA S S7202E7TKMCE

CONTENTSINTRODUCTIONSOLID STATE TRANSFORMER(SST)NEED FOR SST IN WIND ENERGY

SYSTEMSST INTERFACED WIND ENERGY

SYSTEMCONCLUSION

INTRODUCTIONThe solid-state transformer (SST) is one of

the key elements in power electronic-based microgrid systems.

Wind power is an uncontrollable resource , also makes for a challenging integration of large WFs into the grid, particularly in terms of stability and power quality

Integration of SST with wind energy systems effectively replacing the conventional transformer and reactive power compensator , so as to increase the flexibility of wind energy system.

Solid state transformer

The basic idea of the SST is to achieve the voltage transformation by medium to high frequency isolation, therefore to potentially reduce the volume and weight of it compared with the traditional power transformer.

“ELECTRONIC TRANSFORMER”(SST)

Fig.1

Key components High frequency transformers Power electronics converters *AC to DC converters *DC to DC converters *AC to DC inverter

Functional view of SSTInputpart Isolated DC-DC converter

Output part

AC INPUT

Actual view of SST

Fig.3

STAGE ONE

STAGE TWO

STAGE THREE

AC-DC CONVERSION

DC-DC CONVERSION

DC-AC CONVERSION

Fig.4

HF trans.

Note; high frequency transformer(HF trans)

STAGE ONEIn this stage is a three-phase ac/dc rectifier

that regulates a high-voltage dc bus (and ac voltage when for reactive power compensation) is used.

It produce low distortion grid current.DC voltage regulation.

STAGE TWO1) consists of a Dual active bridge(DAB), a high-

frequency transformer. DAB converter gives;1) electrical isolation2) high reliability3) ease of realizing4) soft-switching control 5) complete symmetry of configuration that

allows seamless control for bidirectional power flow.

Active power flows from the bridge with leading phase angle to the bridge with lagging phase angle.

primary bridge leading secondary bridge by a phase angle of ϕ, the power flows from the primary to the secondary.

STAGE THREEDC-AC converter is used to convert the dc

voltage in desirable voltage.

ADVANTAGE An excellent utilization of distributed

renewable energy resources and distributed energy storage devices.

Power factor control. Fast isolation under fault conditions due to a

controlled SST. Control of both AC and DC loads can be done

using the SST

WIND ENERGY SYSTEM

Fig.6

NEED FOR SST IN WIND ENERGY SYSTEMNormally SCIG is used in wind energy systema capacitor bank is generally placed at the

terminal of the wind generator for the local reactive power compensation(which is necessary for the operation of the system)

The nature of WFs is that their operation is highly dependent on the active and reactive powers transferred to the grid

In any interfacing system there is need for conventional transformer and reactive power compensator.

SST-interfaced WF architectures effectively replacing the conventional transformer and reactive power compensator.

SST INTERFACED WIND ENERGY SYSTEM

Fig.7

The local capacitor bank, two conventional transformers, and the STATCOM are all functionally integrated into a single SST

From the working of SST, it is revealed that reactive power compensation, active power compensation and voltage conversion can be done by SST.

OPERATION OF SSTAc power from wpp is convert in to dc power.Hence ac power can be convert in to dc

regulated power, gives pf improvement, voltage control .

In Dc-dc isolation, it isolate input and out put side, power can flow in both direction since DSB is used.

High frequency transformer reduce the size of over all system, provide reactive power compensation,active power compensation.

Dc-ac inverter gives both ac,dc output regulation.

CONCLUSIONEnergy crisis calls for a large penetration of

renewable energy resources, among which wind energy is a promising one. Voltage and frequency regulation is vital to meet the grid code.

SST solve almost problems that make this system cannot connect to grid .

REFERENCES  Xu She, Alex Q. Huang, Fei Wang and Rolando Burgos” Wind Energy System With Integrated

Functions of Active Power Transfer, Reactive Power Compensation, and Voltage Conversion”- IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 60, NO. 10, OCTOBER 2013

  Hengsi Qin,and Jonathan W. Kimball,” Solid-State Transformer Architecture Using AC–AC Dual-

Active-Bridge Converter”- IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 60, NO. 9, SEPTEMBER 2013

Jianjiang Shi, Wei Gou, Hao Yuan, Tiefu Zhao and Alex Q.” Research on Voltage and Power Balance Control for Cascaded Modular Solid-State Transformer” IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 26, NO. 4, APRIL 2011

R. Vibin1, K. Malarvizhi2” Power Flow Control Scheme for Wind Energy Conversion System using FACTS Controller” International Journal of Modern Engineering Research (IJMER) Vol.2, Issue.3, May-June 2012 pp-644-648

Nijaz Dizdarevic* and Matislav Majstrovic” Reactive power compensation of wind energy conversion system by using Unified Power Flow Controller” Int. J. Energy Technology and Policy, Vol. 3, No. 3, 2005

Xu She1, Alex Huang and Rolando Burgos2” Review of the Solid State Transformer Technologies and its Application in Power Distribution System”

Gary L. Johnson” WIND ENERGY SYSTEMS” Electronic Edition 

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