Voltage quality regulation in Sweden
Lars Ström, Math Bollen, Rémy Kolessar
Energy Markets InspectorateEskilstuna, Sweden
Frankfurt (Germany), 6-9 June 2011
Responsibility of the network operator Monitoring only for internal use, no publication The regulatory process is triggered by a complaint Step 1: try to reach agreement Step 2: the regulator investigates the case Step 3: the regulator can enforce measures by the
network operator
Lars Ström – Sweden – S2 – 168
Voltage quality in Sweden
Frankfurt (Germany), 6-9 June 2011
What is acceptable voltage quality?
Existing situation: EN 50160 Soon: a new set of limits
100% values for most of the EN 50160 levels EN 50160 for flicker New requirements for dips and swells Limits on duration of interruptions
No complaints = acceptable quality
Lars Ström – Sweden – S2 – 168
Frankfurt (Germany), 6-9 June 2011
Voltage-quality variations
Harmonics EN 50160 levels hold 100% of time MV levels for HV harmonics 17 – 25
Unbalance At most 2%, 100% of time
Flicker 95% of Plt during one week less than 1.0
Slow voltage variations All 10-minute values between 90 and 110%
Lars Ström – Sweden – S2 – 168
Frankfurt (Germany), 6-9 June 2011
Responsibility sharing curve
Installations should tolerate these dips
Limitations on the number of dips
Duration of the dip
Res
idua
l vol
tage
Lars Ström – Sweden – S2 – 168
Frankfurt (Germany), 6-9 June 2011
Voltage dips: Swedish regulation
Installations should tolerate these dips
A reasonable number of dips is acceptable
Dips are unacceptable
Duration of the dip
Res
idua
l vol
tage
Lars Ström – Sweden – S2 – 168
Frankfurt (Germany), 6-9 June 2011
How to choose the curves?
Dips, up to 45 kV CIGRE/CIRED/UIE working group C4.110
Dips, above 45 kV Discussion between the stakeholders
Swells, up to 1 kV Protection requirements microgeneration Highest overvoltages during earthfaults Experiments on equipment damage
Lars Ström – Sweden – S2 – 168
Frankfurt (Germany), 6-9 June 2011
Nominal voltage 45 kV and less
Lars Ström – Sweden – S2 – 168
0.2s 0.5s 1s 5s
40%
70%
90%
60s
Frankfurt (Germany), 6-9 June 2011
Nominal voltage above 45 kV
Lars Ström – Sweden – S2 – 168
0.2s 0.5s 1s 5s
40%
70%
90%
60s
80%
Frankfurt (Germany), 6-9 June 2011
Voltage swells, up to 1 kV
Lars Ström – Sweden – S2 – 168
0.5s 5s
111%
115%
60s
135%
Frankfurt (Germany), 6-9 June 2011
Interruptions – maximum duration
Lars Ström – Sweden – S2 – 168
Frankfurt (Germany), 6-9 June 2011
Conclusions
New specification on what is considered acceptable voltage quality
Variations: 100% of time Dips and swells: responsibility sharing Interruptions: maximum duration
Experience to be gained on what are reasonable numbers of dips and swells
Lars Ström – Sweden – S2 – 168