Tuesday, August 6, 2013

LOAD FLOW ANALYSIS



LOAD FLOW ANALYSIS

For load flow analysis following data is required:

1.1 Bus Data
Required data for load flow calculations for buses includes:
1. Nominal kV
2. %V and Angle (when Initial Condition is set to use Use Bus Voltages)
3. Load Diversity Factor (when the Loading option is set to use Diversity Factor)

1.2 Branch Data
Branch data is entered into the Branch Editors, i.e., Transformer, Transmission Line, Cable, Reactor, and Impedance editors.
 Required data for load flow calculations for branches includes:
1. Branch Z, R, X, or X/R values and units, tolerance, and temperature, if applicable
2. Cable and transmission line, length, and unit
3. Transformer rated kV and kVA/MVA, tap, and LTC (load tap changer) settings
4. Impedance base kV and base kVA/MVA

1.3 Power Grid Data
Required data for load flow calculations for power grids includes:
1. Operating mode (Swing, Voltage Control, Mvar Control, or PF Control)
2. Nominal kV
3. %V and Angle for swing mode
4. %V, MW loading, and Mvar limits (Qmax & Qmin) for Voltage Control mode
5. MW and Mvar loading, and Mvar limits Mvar Control mode
6. MW loading and PF, and Mvar limits for PF Control mode

1.4 Synchronous Generator Data
Required data for load flow calculations for synchronous generators includes:
1. Operating mode (Swing, Voltage Control, or Mvar Control)
2. Rated kV
3. %V and Angle for swing mode of operation
4. %V, MW loading, and Mvar limits (Qmax and Qmin) for Voltage Control mode
5. MW and Mvar loading, and Mvar limits Mvar Control mode
6. MW loading and PF, and Mvar limits for PF Control mode

1.5 Static Load Data
Required data for load flow calculations for static loads includes:
1. Static Load ID
2. Rated kVA/MVA and kV
3. Power factor
4. % loading for desired Loading Category
5. Equipment cable data

1.6 Capacitor Data
Required data for load flow calculations for capacitors includes:
1. Capacitor ID
2. Rated kV, kvar/bank, and number of banks
3. % loading for desired Loading Category
4. Equipment cable data

1.7 Other Data
There are some study case related data, which must also be provided. This includes:
1. Method (Newton-Raphson, Fast-Decoupled, or Accelerated Gauss-Seidel)
2. Max Iteration
3. Precision
4. Acceleration Factor (when Accelerated Gauss-Seidel method is selected)
5. Loading Category
6. Initial Voltage Condition
7. Report (report format)
8. Update (for bus voltages and transformer LTCs using load flow result)
2.0 DATA COLLECTION FOR MODELING
All the required data for modeling are collected from                                                      .
The following data was collected:
1. Single line diagram of the                                             network.
2. Details of 132kV, 66kV and 33kV substations in the network.
3. Reactance and MW rating of all generators connected to the network.
4. Impedances of all transmission and distribution lines and transformers.
5. Length and type (for e.g. ACSR) of transmission lines from one substation to another.
6. Load details (MVAr and MW) of the existing network.

2.1 Substation Details
Details of substation were obtained from                                         . It includes
1. Type of substation
2. Rating of transformers in the substation
3. A 4 letter code word for providing a unique ID in ETAP software.

2.2 Load Details
Details of static load connected to the 33 kV and 132 kV buses were collected. Load details include
1. The MVA rating
2. Power factor of operation

Installed Capacity (MW)

Maximum Demand  (MW)

132 kV Lines Circuits (Km)

66 kV Lines Circuits (Km)

33 kV Lines Circuits (Km)

Connected Loads (MW)

No. of 132 kV substation

No .of 66 kV substation

No. of 32 kV substation