A Study on Improvement of Voltage Profile of a Power System Using FACTS Device (STATCOM)

PRESENTED BY

Md. Atikul IslamID No: WUB09/09/33/971Sujan Kumar GhoshID No: WUB09/09/33/975Department of EEEWorld University of Bangladesh

SUPERVISED BY

Raktim Kumar MondolLecturerDepartment of EEEWorld University of Bangladesh

BACKGROUNDBACKGROUND

The term, Flexible AC Transmission Systems “FACTS” covers several power electronics based systems used for AC power transmission and distribution.

Important applications in power transmission and distribution involve devices such as SVC, SC as well as TCSC and STATCOM.

Static VAR Compensation (STATCOM) is one of the advance power systems known as FACTS controllers, which provides fast and continuous capacitive and inductive reactive power supply to the power system.

Maintain or improve voltage stability, grid reliability and reduce overall power losses.

EXECUTIVE SUMMARYEXECUTIVE SUMMARYIn this paper we studied the shunt operation of FACTS controller. FACTS devices are mainly use for solving various power system steady state control problems such as voltage regulation, power flow control, and transfer capability enhancement. FACTS device allows transmission systems to be more efficiently. STATCOM is a shunt FACTS device which can be used to regulate the flow of reactive power in the system independent of other system parameters. The study of STATCOM including phase angle control are carried out. STATCOM has no long term energy support on the dc side and it cannot exchange real power with the ac system. In the transmission systems, STATCOM primarily handle only fundamental reactive power exchange and provide voltage support. STATCOM Operating, maintenance and investment cost are lower than others.

METHODOLOGYMETHODOLOGY

Design using different resources found from internet, books, researches and manuals.

Implemented and check the circuit operation using MATLAB, Multisilm, 5spice.

OBJECTIVESOBJECTIVES

The main objective of FACTS (Flexible AC Transmission Systems) is to increase the useable transmission capacity of lines and control power flow.

To enhance power system stability by using STATCOM.

ADVANTAGES OF FACTSADVANTAGES OF FACTS

Improved power transmission capability.

Improved system stability.

Improved power quality.

Improved load sharing between parallel circuits

Decreased overall system transmission losses

TYPE OF FACTS DEVICESTYPE OF FACTS DEVICES

FACTS DEVICES

SERIES SHUNT COMBINED

SSSC TCSC SVC STATCOM UPFC IPFC

COMPARISON BETWEEN STATCOM AND SVCCOMPARISON BETWEEN STATCOM AND SVC

STATIC SYNCHRONOUS COMPENSATOR STATIC SYNCHRONOUS COMPENSATOR (STATCOM) (STATCOM)

STATCOM is a static synchronous generator as shunt static VAR compensator.

It’s capacitive or inductive current can be controlled independently of the system voltage.

The STATCOM scheme in parallel with AC power grid system.

STATCOM controlled by a dynamic controller.

BLOCK DIAGRAM OF STATCOMBLOCK DIAGRAM OF STATCOM

STATCOM CONVERTER CABINETSTATCOM CONVERTER CABINET

The very compact power electronic modules are placed inside a cabinet structure. Only a few additional external components are needed, such as STATCOM transformer, grid filter and heat exchanger.

OPERATING PRINCIPLE OF STATCOMOPERATING PRINCIPLE OF STATCOM

Figure 4. STATCOM Principle diagram

CONTROL CHARACTERISTIC OF A CONTROL CHARACTERISTIC OF A STATCOMSTATCOM

We can say that; If EI> ET the STATCOM is drawing a capacitive reactive current and if EI< ET the STATCOM is inductive reactive current. Q=EI(EI-ET)/X

CONTROL FUNCTION OF STATCOMCONTROL FUNCTION OF STATCOM

F=VP-VSP=0

The control of the STATCOM voltage magnitude should be such that the specified bus voltage and the STATCOM voltage should be equivalent and there should be no difference between them.

Vsp is the specified voltage for the bus.

BENEFITS OF USING STATCOMBENEFITS OF USING STATCOM

STATCOM has no inertia.

Better dynamics response.

Lower investment cost.

Lower operating and maintenance cost.

Figure. Sample three-Bus study test system with the STATCOM located at bus B2 to stabilize the AC system.

THREE-BUS SYSTEMTHREE-BUS SYSTEM

Figure. Without STATCOM Figure. With STATCOM at Load Bus 4

DIAGRAM OF 5 BUS POWER SYSTEMDIAGRAM OF 5 BUS POWER SYSTEM

STATCOM is a FACTS device which can be used to regulate the flow of reactive power in the system independent of other system parameters. Here we experimentally set STATCOM at different bus and show the results by using MATLAB.

RESULTSRESULTS

MVAR provided

by STATCOM

Load Bus voltage magnitude with STATCOM

(P.U)

Total voltage

deviation of load

busV2 V4 V5

5 0.9616 0.9323 0.9716 0.420410 0.9617 0.9417 0.9738 0.417415 0.9617 0.9509 0.9760 0.417120 0.9617 0.9599 0.9782 0.423525 0.9617 0.9688 0.9803 0.4398

Here we observed that when MVA rating is 15 MVA then the total voltage deviation is minimum which is 0.4171. After that the total voltage deviation of load bus is increased rapidly.

Bus No

Load bus voltage magnitude without

STATCOM (P.U)

1 1.0400

2 0.9616

3 1.0200

4 0.9227

5 0.9692

RESULTS ON GRAPH RESULTS ON GRAPH

Bus 2Bus 4Bus 5

In the above results we observed that STATCOM at bus 4 is better than 2 and 5. Because voltage deviation is minimum and MVA is good. Although MVA of bus 2 and 4 are same but total voltage deviation of bus 4 is smaller than total voltage deviation of bus 2 . Which is expected for us.

DISCUSSIONDISCUSSION With the history of more than three decades and widespread

research and development about FACTS devices, we can say : From an economical point of view: FACTS devices help to

distribute the electrical energy more economically through better utilization of existing installation there by reducing the need for additional transmission lines. Financial benefit from FACTS devices comes to increased transmission capability. More power can be transmitted over existing or new transmission grids at a lower price.

From an environmental point of view: The construction of new transmission line has negative impact on the environment. STATCOM enables the transmission of power over vast distances with less impact on our environment. Furthermore, the saving in transmission losses may well bring a corresponding decrease in need for generation, with less toll on the environment.

CONCLUSIONCONCLUSION

The result shown above by modeling the system in MATLAB and simulating their result shows that by MATLAB simulation studies. Thus the proposed controller shows better performance the power system oscillations. STATCOM provides the most reliable and efficient solution. If we install STATCOM to our existing transmission line, we can minimize huge amount of transmission loss and add extra KV in our national grid that can fill our shortage of demand and Improved power transmission capability in Bangladesh. These calls for the right solutions as far as power transmission facilities.