Major Issues Grid integration on Solar pv plant

Major Issues Grid integration on Solar PV Plant

• 
  Voltage fluctuation and regulation
  
• 
  Short circuit contribution
  
• 
  Unintentional islanding
  
• 
  Frequency variation and regulation
  
• 
  Harmonics & Flickers
  
• 
  Reactive power Requirement
  

Voltage fluctuation and regulation
It is considered that electricity is distributed at the consumer’s terminal within the tolerable limit. The normal allowable voltage range is ±5% of the nominal value. When large RES is integrated with lightly loaded feeders, the impact is unbearable. Whenever there is any change in load, the voltage fluctuation occurs at PCC. The voltage fluctuations and dips occur due to earth leakage faults and earth short-circuits located in the electrical power system (EPS). These faults weaken the voltage quality at PCC, based on fault situations. This is a significant element, particularly for solar and wind energy sources which possess irregular characteristics due to the wind speed disparity and solar irradiance that changes with time. The sensitivity of both electrical and electronic appliances that contributes to the life span deficiency of maximum devices is due to the voltage deviation

Over voltage

• 
  Voltage rise is experienced on a feeder depends on multiple factors, including the configuration of the feeder and the location of the PV and voltage control equipment, such as capacitor banks and voltage regulating transformers.
  
• 
  High penetrations of PV systems can cause the ampacity ratings of circuit elements to be exceeded in a number of ways. Perhaps most intuitively, the total generation from attached PV systems can overload circuit elements located between PV systems and load centers on a given circuit. Additionally, PV can mask load that can overload circuit elements if the PV disconnects.
  
• 
  Also, although load is often quite diverse, PV systems located relatively close to each other are generally fairly coincident (depending on their orientation). In such cases, multiple instances of PV systems that are sized to offset the attached load (e.g., in a residential subdivision) may overload circuit elements because of the coincident nature of the peak PV output relative to the diverse nature of the peak load.
  
• 
  When examining overloads, consideration should be given to both normal system conditions and a contingency loss of circuit segments.
  
• 
  The LSS Plant and its apparatus shall be compatible with the insulation levels of the distribution system.
  

CEA GUIDELINES: The generating station connected to the grid, shall remain connected to the grid when voltage at the interconnection point, on any or all phases (symmetrical or asymmetrical overvoltage conditions) rises above the specified values given below for specified time