⇒ Voltage levels  
⇒ Capacity  
⇒ Voltage Regulation  
⇒ Tie-line Stability  
• Interface standards—specially associated with strength quality, which in flip determines  
the renewable ability limit. Power Quality troubles are:  
⇒ Harmonic Distortion  
⇒ Voltage Transients and Sags  
⇒ Voltage Flicker  
⇒ Step Load Voltage  
• The company ability of the windfarm and the related wind strength dispatch  
troubles.  
⇒ Load following  
⇒ Scheduling  
⇒ Reserve  
• Response to odd conditions:  
⇒ Voltage disturbances  
⇒ Faults  
 

Beyond this most strength (Pmax), the Tie-Line turns into volatile and could lose  
synchronism. This is known as the consistent nation balance restrict of the gadget.  
• In practice, the road loading need to be stored nicely beneath Pmax, to permit for transients including  
surprising load steps and gadget faults. The most strength the road can switch with out losing  
the stableness in the course of transients is known as the dynamic balance restrict.  
• In ordinary systems, the strength angel need to be stored beneath 20º to guarantee dynamic balance.  
POWER QUALITY  
The fast growth withinside the call for of strength, depletion of fossil gasoline and environmental threat  
to sustainable improvement are the simple motives for the quick improvement withinside the subject of  
Renewable Energy (RE) sector. Hence, the idea of micro-grid , which makes use of power  
reassets including photovoltaic (PV), wind turbine (WT) and gasoline cell (FC) got here in to picture.  
These power reassets are located withinside the load middle and may be seamlessly linked or  
disconnected to the low voltage software grid. Due to intermittent nature of RE reassets, more  
than one supply is normally mixed to shape a HPS. These reassets makes use of strength  
conditioning gadgets like, DC-DC increase converter to elevate the voltage stage to nominal value  
or a DC-AC converter to combine the assets to the software grid. However, the proliferation  
of those strength electronics switching gadgets introduces an alarming challenge amongst the  
business power patron and additionally to the software grid; that is termed as PQ problems Among  
the numerous PQ problems notices so far, voltage transients, voltage sag and swell, harmonic  
distortion and flicker are of key concerns. In a view to enhance the strength first-class a new  
method turned into advised wherein replaces the inverter via way of a DC motor -Alternator set to  
combine the RE reassets. In this framework, an try is made to degree and examine the  
numerous PQ indices for HPS version with the 2 unique modes of grid integration, i.e.  
inverter mode and its counterpart i.e. a DC motor –Alternator set mode of grid integration.  
Various PQ indices including voltage variation, voltage sag and swell, voltage imbalance,  
flicker, Total Harmonic Distortion (THD) are measured on the client terminal via way of using  
each integration schemes. Simulation consequences suggest that the first-class of strength injected into  
the grid via a MG set is advanced to that coming from inverter.