04-08-2010, 07:18 PM
Introduction
Voltage sags and momentary power interruptions are probably the most important PQ problem
affecting industrial and large commercial customers.They are mainly caused due to the fault occurring at some location in the supply grid. Interruptions occur when the fault is on the circuit supplying the
power to the customer. But the voltage sags can occur even if the fault site is far away from the customer's site. sensitive customer equipment to drop out can be produced by the voltage sags which last for only as short as 4-5 cycles. How much the end devices gets affected by the voltage sag is dependent upon duration and magnitude of voltage sags.
Characteristics of Voltage Sags
faults on the power system.
, Motor starting etc are the major causes of voltage sags maybe in different magnitudes.
Voltage -sag analysis methodology
The method basically consists of four steps:
1)Load Flow:
here, load flow representing the existing or modified system is required with an accurate zero-sequence representation.
2)Voltage Sag Calculation:
The line-line, line to ground, line to line- to ground and three phase sliding faults are
applied to all the lines in the load flow.
3)Study of Results of Sag- Analysis:
The results can be tabulated and displayed in many different ways to recognize difficult aspects.
4)Equipment Sensitivity Studies
For full details refer this report:
VOLTAGE SAG ANALYSIS.pdf (Size: 214.54 KB / Downloads: 605)
Voltage sags and momentary power interruptions are probably the most important PQ problem
affecting industrial and large commercial customers.They are mainly caused due to the fault occurring at some location in the supply grid. Interruptions occur when the fault is on the circuit supplying the
power to the customer. But the voltage sags can occur even if the fault site is far away from the customer's site. sensitive customer equipment to drop out can be produced by the voltage sags which last for only as short as 4-5 cycles. How much the end devices gets affected by the voltage sag is dependent upon duration and magnitude of voltage sags.
Characteristics of Voltage Sags
faults on the power system.
, Motor starting etc are the major causes of voltage sags maybe in different magnitudes.
Voltage -sag analysis methodology
The method basically consists of four steps:
1)Load Flow:
here, load flow representing the existing or modified system is required with an accurate zero-sequence representation.
2)Voltage Sag Calculation:
The line-line, line to ground, line to line- to ground and three phase sliding faults are
applied to all the lines in the load flow.
3)Study of Results of Sag- Analysis:
The results can be tabulated and displayed in many different ways to recognize difficult aspects.
4)Equipment Sensitivity Studies
For full details refer this report:
VOLTAGE SAG ANALYSIS.pdf (Size: 214.54 KB / Downloads: 605)