Static Var Compensator to Improve Profile Voltage

In power systems, there are two kinds of modeling the load is static load and dynamic load.

1) Model Static Load

Static load model is a model that represents active and reactive power as a function of the bus voltage and frequency. Static load in response to changes in voltage and frequency is reached quickly, so it tends to steady-state condition. Static load models are typically used for components such as resistive loads and lighting loads, and is also sometimes used to approach the dynamic components.

2) Model Load dynamic

Dynamic load model is a model that represents the active power and reactive follow the dynamics of the system variables, so that the condition can change at any time.

F. Drop Voltage

The Drop Voltage is the amount of voltage that is missing on a conductor. The voltage drop across the power line is generally proportional to the length of the channel and the load, and inversely proportional to the cross sectional area of the conductor. The magnitude of the voltage drop expressed either in percent or in the amount of Volt.

G. Static Var Compensator

Static Var Compensator or called SVC is one of the FACTS equipment Device consisting of a reactor component with a large set of inductive reactive power compensation and capacitor as a source of reactive power, power electronics equipment as well equipped as a switching device. Broadly speaking, the function of which is to preserve SVC (controller) voltage stability remain constant at its face value.

SVC is a generator / load connected shunt static VAR where output is set for the exchange of inductive or capacitive currents in order to maintain or control the power system can be varied. TCR (Thyristor Controlled Reactor) at the fundamental frequency can be treated as a variable inductance

………………………………………………. (5)

Where, X_V is a variable reactance SVC while X_L is the reactance caused by the fundamental frequency without control thyristor and α is the angle of ignition so that the total equivalent impedance of the controller can be expressed in:

……………………………………….. (6)

Value rx = X_C / X_L is given by the controller limit ignition angle limit of value fixed in accordance with the design. control law The steady state contained in the SVC typical VI characteristic figure 2.3 is

…………………………………………………….. (7)

where V and I are rms voltage and current magnitude and Vref is the reference voltage. Typical values for slope X_SL is 2 to 5%, tehadap SVC base; The value is necessary to avoid passing the limit of bus voltage variation is small. A typical value controlled voltage range of Vref.[11] [12]

Figure 3. V I characteristics instate SVC steady

H. Power Flow method

By using the Newton Raphson method to analyze the power flow by forming a non-linear algebraic equations of power flow calculation can be determined by performing a comparison between the voltage change in voltage angle and the magnitude of the voltage with active power changes and reactive power (k)).[11]In the mathematical equations of power flow can be written as follows:

…………………………… (8)

Where: is the value of active power (MW)

is the value of reactive power (MVAr)

I. Software ETAP Power Station

ETAP (Electric Transient and Analysis Program)is a software full-graphics that can be used to design and test the condition of the existing electric power system. ETAP can be used to simulate the electrical power system offline in the form of a simulation module, monitoring the operation data in realtime, simulation, real time system optimization, energy management systems andsimulation of intelligent loads hedding. ETAP is designed to handle a variety of conditions and electric power system topologies both in the consumer side of the industry as well as to analyze the performance of the system at the utility. software Thisis equipped with facilities to support the simulation of such networks AC and DC (AC and DC networks),the design of cable networks, grid earth (groundgrid), GIS, panel design, arc-flash, coordination of protective devices (protective devices coordination /selectivity),and AC / DC control system diagram.

ETAP Power Station also provides a library that will simplify the design of an electrical system. library This can be edited or can be added to the information equipment. This software works by plant (project).Each plant must provide modeling support equipment associated with the analysis that will be performed. For instance generator, load data, channel data, etc. A plant consists of a sub-set of the electrical system that require special electrical components and interconnected. In Power Station, each plant must provide a data base for that purpose.

ETAP Power Station can be used to describe a single line diagram graphically and conduct some analysis / study of the Load Flow Short Circuit, the motor starting, harmonics, transient stability, protective device coordination, and Optimal Capacitor Placement.[13]

A few things to note in working with ETAP Power Station are:

1. One Line Diagram, shows the relationship between the components / equipment so as to form an electrical system.
2. Library, information about all of the equipment that will be used in the electrical system. Data electrical and mechanical equipment details / full can simplify and improve the results of simulation / analysis.
3. The standard is used, usually refers to the IEC or ANSI standards, the frequency of the system and method – the method used.
4. Case Study, containing parameters – parameters related to the method of study to be performed and format of analytical results.
5. Completeness of data from each element / component / electrical equipment on the system that will be very helpful analyzed the results of the simulation / analysis can approach the actual operational state.[13]

J. Genetic Algorithms on OCP tool within ETAP

Optimal Capacitor Placement (OCP) is one of the tools in the software ETAP Power Station which uses genetic algorithm for optimal capacitor placement. Genetic Algorithm is an optimization technique that is based on the theory of natural selection. An algorithm starts with the generation solutions with the diversity to represent the characteristics of the overall search space. By mutation and crossover characteristics that both have to be taken to the next generation. The optimal solution can be achieved through repeated generations. The most common method is based on a rule of thumb followed by running multiple power flow studies for fine tuning size and location. multiple power flow for fine tuning size and location.

K. Objective Function

The objective of the placement problems SVC is to improve the voltage profile and reduce the total power losses in power systems installed. The objective function is obtained from two terms. The first is the placement of SVC with the approach of the capacitor and the second is the total power loss. The objective function associated with the placement of the capacitor consists of a total power loss and the capacity of the capacitor. In general, the optimal capacitor placement and capacity can be written in the following equation [14]:

……………….. ……. (9)

Subject to:

……………………………….. (10)

…………………………………….. (11)

Where:

P _loss= Total power loss

J = Total Bus

= Placement capacity capacitors on the bus j

V_j= voltage rms at bus j

V _min= minimum voltage is allowed (pu)

V _max= maximum voltage that allowed (pu)

= maximum capacitor capacity permissible

= minimum capacity capacitor bank

L. Operatinal Constraint

Along the feeder are required to remain within upper and lower limits after the addition of capasitors on the feeder. Voltage constrains can be taken into account by voltage.

M. Placement of Static Var Compensator

placement static var compensator used approach OCP. OCP is the optimal capacitor placement that exist in software ETAP power station which will be described in research methodology. Optimal placement of capacitors in the power system has many variables including the capacitor capacity, optimal placement, voltage and harmonics. Where in determining placement and optimum capacity, types of capacitors can be adjusted based on conditions on the ground. Namum considering these variables, making optimal placement becomes very complicated. So as to simplify the analysis, the type of capacitor can be assumed as follows:

1. The system is in equilibrium (balanced)

2. All types are considered constant load

N. Capacitors Capacity

Capacitors In determining capacity, used capacity started based standard smallest capacity of capacitors and multiples thereof. So based on these standards, the capacity of the capacitor can be used as a discrete variable. and will be used as the capacity of the SVC.

In the analysis of the placement and the determination of the optimum capacity of capacitors to improve voltage profile and reduction in power losses, papers It uses the standard IEEE as a reference point in the implementation process and workmanship. Testing and research with survey data obtained from PT. PLN (Persero) APP TJBTB Probolinggo. With the data obtained, it can be simulated transmission system APJ Pasuruan 70 kV and 150 kV using software ETAP Power Station. Simulations can be done in the form of power flow or Load Flow, which is to know the profile of the voltage, active power, reactive power and losses that occur in the system 70 kV and 150 kV After conducting a study of power flow it is known conditions of the bus who suffered voltage drop (under voltage).If there are conditions that decrease the bus voltage below the allowable margin (0.95 A. Flow studies

Flowused in the preparation of this study are as follows:

1. Start
2. Drawing single line diagrams.
3. Input data: data generator, a data channel, the data load.
4. Running the simulation Load Flow using Method Newton Raphson
5. To check whether the voltage on the system is at the permitted margin of 0.95 ≤ V ≤ 1.05 pu
6. If “No”Perform simulation process OCP bus to get anywhere into optimal location for placement of the capacitor which is then replaced by the value of the capacitor SVC. Once the process OCP is complete, plug SVC finished.
7. Return to Step 4
8. If “Yes” go to step 8
9. Results and Analysis of the results
10. Done.
11. Flowchart

Figure 4. Flowchart solving

A. Modeling transmission system 70kV – 150kV APJ Pasuruan using software ETAP Power Station

Before running simulation modeling is required in advance PLN APJ Pasuruan sisitem transmission using software ETAP Power Station from pictures in the can when the survey. Modeling Single line diagramis done using software ETAP Power Station and to enter all of the data supports five image simulasi. Transmission system70kV -150kV APJ Pasuruan is still in the shade APP Probolinggo with 12 bus and were able to generate 632.4 MW power P and Q 391,92 MVar of PLTGU. Total peak load on the transmission system APJ Pasuruan P 327.75 129.8 MW Q MVar.

Source: PT PLN TJBTB APP Probolinggo

Figure 5. Single line diagram APP system probolinggo

B. Generating Data transmission line system 70kV – 150k APJ Pasuruan

Table 1. Data Capable of Generating Power transmission system 70kV – 150kV APJ Pasuruan

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Source: PT PLN TJBTB APP Probolinggo

C. Load data transmission systems 70kV – 150kV APJ Pasuruan

Table 2. Data transmission system peak load of 70kV – 150kVAPJ Pasuruan

Source: PT PLN TJBTB APP Probolinggo (peak load data)

D. Line transmission data in system 70kV – 150kV APJ Pasuruan

Table 3. Line transmissiondata in system 70kV – 150kV Pasuruan

Source: PT PLN TJBTB APP Probolinggo

E. Modelling single line transmission system diagram 70kV – 150kV APJ Pasuruan

Creating modeling a single line diagram70KV transmission systems – 150kV APJ Pasuruan on software ETAP Power Station is the first step in the analysis. Where in this modeling will be included all the data – technical data which includes capacity, generation, channel, transformer, step-up the transformer and the load.

Figure 6 Modelling Single Line Diagram of the transmission system 70kV – 150kV APJ Pasuruan

F. Simulation Load Flow using Software ETAP Power Station on the conditions of the base case

Simulation load flow is intended to determine the initial condition of the system, determine the value of the voltage rating on every bus, knowing that the power in each channel and obtain the value of active and reactive power on the bus. Insimulation load flow thisusing methods Newthon Rhapson.

Figure 7. After the run with load flow in base case conditions.

Table 3. Profile voltage conditions of the base case

Figure 8. Graph voltage profile condition of base case

Based on the load flow inconditions basecase aboveand have been known to occur outside the voltage breach margin the permitted of 0.95 pu to 1 05 pu in Bangil2 bus, bus Bulu kandang, Pandaan bus, and the bus Sukorejo, it can be improved voltage profile by using analysis of Optimal Capacitor placement (OCP) for placement and capacity SVC.

G. Placement Analysis

 

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