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