What is NA?
- — A tool integrated on GIS based data platform which simulates electrical distribution network & parameters to carry out various power system analysis studies
WHY NA?
- — To study and evaluate the quality, reliability and performance of an existing network.
- — To design optimum augmentation plans for the overall improvement & stability of the network.
Solution
Architecture:
System
Integration Diagram:
NA modules under the scope of R-APDRP
Balanced Load Flow Analysis
A numerical tool which is used to analyze the behavior of electrical system for a given operating condition (static operating condition) by determining the Power flow in all series devices, Voltages at all nodes, system loss and load generation balance.
Loads are equal in all phases and treated as a single phase load.
Network is assumed to be balanced.
Losses are restricted to phase conductors
The basic parameters in a LFA are
P - Active power in the network
Q - Reactive power in the network
|V| - Magnitude of bus voltage
δ - Angle of bus voltage w.r.t common reference
A slack bus delivers or absorbs infinite power at p.u voltage of 1 and a constant δ.
A load bus has a constant P and Q while it’s V and δ vary.
A generator bus has constant P and |V| while it’s Q and δ vary.
Balanced LFA – Iterative Techniques
LFA Basics
Unbalanced Load Flow Analysis
Loads are considered in their unbalanced manner.
Network is treated to be unbalanced.
Lines are not transposed.
Positive, negative, and zero sequence impedance, phase to phase impedance, self and mutual impedances play an important role.
This leads to a Complex model of the system.
Specific to traction and distribution systems.
Short Circuit Studies
Performed to determine the magnitude of currents flowing throughout the power system after a fault occurs.
It calculates the Fault Current / MVA(or KVA) in each element of the interconnecting network and the post fault voltage magnitude and phase angle at each Pole/Bus/node through numerical analysis tools.
Fault Types:
1. Three phase fault:
Ia1=[Vf/(Z1+Zf)] ; Ia2 = 0 ; Ia0 = 0
2. Single line to ground fault
Ia1=Ia2=Ia0=[Vf/(Z1+Z2+Z0+3Zf) ]
3. Line to line fault
Ia1 = -Ia2 = [Vf/(Z1+Z2+Zf)] ; Ia0 = 0
4. Double line to ground fault
Ia1 = [Vf/Z1+{Z2Z0/(Z2+Z0)}]
Why SCS?
Planning and operational study
Standardising Plant & Equipment specifications
Evaluation of fault withstanding capacities of existing breakers
Input for Protection Co-ordination
Optimization Studies:-
Line Reconductoring
Replacement of the existing conductor on the feeder with an optimal conductor size for optimal length of the feeder since it is the size of the conductor that decides current density and resistance.
This scheme is applied when
- Network reconfiguration is not possible
- The existing conductor is no more optimal due to rapid load growth
Re-conductoring depends on Load expected to serve and capacity required in future
DT Relocation
DTC relocation involves the change of feed point.
This scheme is adopted as an immediate solution.
The new point of connection can be determined by feasibility study.
Merits
- Supports further reconfiguration
- Investment required is less
Demerits
- The extent of voltage improvement is limited
- For further improvement of voltage profile we have to adopt for other methodologies which involves extra investment.
Load Allocation
The module shows a report of Feeder-wise allocation of load based on kVA consumption of the feeder.
New Consumer Connection
In a distribution system, load extension is a regular requirement. For the system to remain robust, an analysis is required to estimate the stress on the exiting network topology.
The module takes the new consumer load as input and performs a Load flow analysis.
A feasibility report states the following feasibility criteria:
- The voltage regulation is maintained at all poles accordingly.
- The loading on DTC is within the limit.
- The thermal loading on the feeders is within the limit.
Express Feeder
Express feeder can be stated as the feeder from source point to a DT point without any intermediate tapping.
Generally used to improve the voltage profile in the network.
Express feeder module is developed in the same lines, that for the network under consideration, the software itself suggests an optimal point to which the express feeder has to be laid.
Voltage regulator placement
It is a tool that suggests an optimal placement of a voltage regulator in the network under consideration such that the overall network voltage profile improves. The basis is a load flow analysis.
NA Tools
Line/Cable parameter Calculation
This is used for calculating line parameters such as Resistance, reactance & susceptance for an unknown or known type of lines or cables.
Ground Grid Design
This is used for estimating grounding design of a substation. It suggests whether chosen earth electrodes are best suited depending on the soil resistivity, support & temperature.
Line Support Evaluation
This is to evaluate the safety of design of a pole (type, length, etc) selected to support a feeder segment based on working load in kg & other physical parameters.
Load Modeling
This module finds the voltage drop for lumping of the entire load at one point. This point is theoretically determined by the type of loading as follows:
Bulk load – At tail end
Uniformly increasing load – At 2/3 rd of length
Uniformly distributed load – At 1/3 rd of length
Integration with other Business Processes
I. Integration with MDAS for analyzing the real time performance of the network i.e. On-Demand LFA.
II. Integration for New consumer connection feasibility.
III. Integration for real-time accumulation of Technical loss calculation for Energy audit.
IV. Integration with CRM or concerned process for SOR required in Financial Analysis like Cost Estimation.
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