Load Flow Analysis is carried out to observe the Loading Pattern and the conditions of poor Average Power Factor maintained in the Plant and to suggest suitable remedial measure to maintain healthy Average Power Factor thereby achieving Reduction in MD KVA, Reduction in KWHr, avoidance of PF penalty and to avail benefits of PF incentive etc.
Power Flow Study Conduction
The Power Flow Study is conducted by optimizing the number of nodes to be studied depending on the scheme suitable for the Plant.
For the Medium Industries with HT services, measurement is done at the main incomer to provide a Centralized PF Correction Solution, aiming at PF improvement and MD kVA reduction.
For Heavy Industries measurement is done at the Main incomer, MCC, SSBs and major individual loads to provide a distributed PF Correction System to avail benefits of reduction of Distribution losses in the feeding cable, PF improvement and MD kVA reduction.
The measurements are done using high speed Power Quality Analyzer. Various instantaneous Power Parameters are recorded for Analysis & Evaluation of opt System. The Parameters logged includes the following:
The recording interval is selected as appropriate to the study, depending on the Loading pattern.
- > Load Flow – kW, kVA, kVAR, true pf, displacement pf etc.
- > Electrical Data – Voltage, current & frequency
- > Distortion Data: Distortions in I & V.
Power Flow Evaluation
The Power Flow data are evaluated along with the EB Bill details to identify the following, by analyzing the Trend of the various parameters over a period of time.
- > Exiting Power factor level
- > The Base load compensation requirements
- > Transformer compensation requirements for HT services
- > Peak load requirements
- > Load variation Pattern
- > Voltage Profile
- > Harmonic Distortion Profile
The Main integration Period (MIP) is selected depending on the load variation pattern. For highly fluctuating load, MIP is usually selected as low as 1 second. For continuously varying load, the MIP is selected matching the load profile optimizing the recording memory for the total recording period.
The total recording period is decided based on the Load Profile and the need of study. For steady load pattern, a sample of an Hour or more duration is sufficient, while for continuous load profile, the recording period is selected to cover one complete load cycle, which is usually done for 24 Hours.
The interpretation of the instantaneous readings, the trend and the minimum, average and maximum values for the MIP at every node is reported supported by the corresponding readings tabulated and the Trend Graphs.
The interpretation of the total study data and the site data will be reported with suitable recommendation of Reactive Power Management Scheme for any identification of the requirement.
The scheme is recommended with the suitable PF Correction System to be located at feasible locations to obtain the maximum benefits that can be committed.
The scheme may also be recommended to be implemented in various Phases depending on the site development and the Load Expansions.
The System selection is done taking into consideration, the base load and Transformer Compensation with suitable minimum step size, the peak load conditions taken care by the total system size and the Load variations taken care by step resolution matching it, if the System is selected as an APFC/DPFC System. The response time of compensation of the System is matched with Load fluctuation by selection of appropriate Relay Characteristics and Switching methods. The System is also designed to avoid any overcompensation at light load conditions or to have fine tuned control over Reactive Power Import/Export as applicable at conditions Regeneration in plants with Cogeneration etc.
The Harmonic Distortion level is also checked for any possible Harmonic amplification on implementation of the System.
The System configuration is also checked for any possible Harmonic resonance with the Network impedance dominantly with the Distribution Transformer depending on its stiffness.
The Voltage Profile and the possible Grid Side harmonic Pollution is also checked by conducting study for a considerably longer duration usually for 24 Hours.
The System specification is arrived based on the various conditions and the statutory conditions. It includes the Fault level, Voltage Profile, the conditions for the protection against Overload and Short Circuits, the operation and control requirements, the ambient Temperature and Ventilation arrangements, the humidity and other physical conditions, the location and accessibility of the system, the space availability and other statutory conditions to be satisfied.
On installation of the System, the performance of the System is validated to meet the committed benefits, by conducting a validation study for a reasonable period, which is usually for 24 Hours, and the performance is monitored for atleast 1 year, which covers the warrantee period.
The benefits usually committed are:
- Power Factor improvement to the committed level
- Avoidance of PF Penalty
- Availing PF incentives
- Reduction of MD kVA
- Avoidance of MD Penalty if any
- Surrendering of Sanction Demand if in Excess
- Reduction of Distribution losses