frankfurt (germany), 6-9 june 2011 1 astrid petterteig, sintef energy research, norway – paper...
DESCRIPTION
Frankfurt (Germany), 6-9 June 2011 Measured power flow into feeder with several DG units - 2 year Frequent changes in power flow Seasonal variations in power generation: High generation when consumption is low & Low when consumption is high Reactive power flow increases with increasing active power generation Measurements Jan March May July Sept Nov Active power Reactive powerTRANSCRIPT
Frankfurt (Germany), 6-9 June 2011
1
Astrid Petterteig, SINTEF Energy Research, Norway – Paper 0840Presented by Dag Eirik Nordgård, SINTEF Energy Research
Smart grid measures to reduce losses in distribution feeders and increase capacity to integrate local small hydro generation
Frankfurt (Germany), 6-9 June 2011
Small hydro power plants (1 - 10 MVA)in areas with low consumption and weak lines
Generation much higher than local consumption Strongly varying generation (river plants without water storage) Long feeders and high voltage levels when the generation is high
Generators consume reactive power to reduce line voltage
Common DG situation in Norway
Frankfurt (Germany), 6-9 June 2011
Measured power flow into feeder with several DG units - 2 year Frequent changes in power flow Seasonal variations in power generation:
High generation when consumption is low & Low when consumption is high Reactive power flow increases with increasing active power generation
Measurements
-12,0
-8,0
-4,0
0,0
4,0
8,0
12,0
1 1281
Ps 09-10
Qs 09-10
Jan March May July Sept Nov Jan March May July Sept Nov
Active powerReactive power
Frankfurt (Germany), 6-9 June 2011
Measured power flow in three different networks for 2 and 3 years: Case I DG unit producing 2.1 MW and consuming up to 1.1 MVAr Case II Measured: 7.1 MVAr into with 11.4 MW out of feeder Case III Measured: 2.8 MVAr into with 5.7 MW out of feeder
Reactive power flow increases with increasing active power generation
Measurements
-12,0
-8,0
-4,0
0,0
4,0
8,0
12,0
1 1281
Ps 09-10
Qs 09-10
Jan March May July Sept Nov Jan March May July Sept Nov
Active powerReactive power
Frankfurt (Germany), 6-9 June 2011
Qs
IsU
Two simplified feeders analysed In different load conditions:
Low load & high generation – Production limited by maximum line voltage High load & low/med. generation – Frequently occurring, no line voltage issues
Compare three strategies for reactive power generation: Qdg = 0All DG units run with zero reactive power Qdg < 0 One or more DG unit consumes reactive power Qs = 0 Coordinated control of reactive power
Focus on feeder losses, Maximum line voltage and flow in sub-station
Reactive power flow strategies analysed:
Frankfurt (Germany), 6-9 June 2011
In networks with several synchronous generators: Generator(s) at the end of feeder consumes reactive power Generator(s) close to sub-station produces reactive powerGoal: Minimize flow of reactive power (Qs) and sub-station current (Is)
Reduce feeder losses (compared to strategy with Qdg<0) Maximize active power generation without violating voltage limits (∆U)
Can increase active power generation (compared to Qdg=0)
Utilize existing network (postpone reinforcement) without increasing losses and reactive power flow
Coordinated control of reactive power
Qs
IsU
Frankfurt (Germany), 6-9 June 2011
22,00
22,22
22,44
22,66
22,88
Stasjon 2 4 6 8 10 12 14 16 18 20 km
Linjespenning - 2 MW last, 20 km FeAl120
13MW Qdg=0
22,00
22,22
22,44
22,66
22,88
Stasjon 2 4 6 8 10 12 14 16 18 20 km
Linjespenning - 2 MW last, 20 km FeAl120
13MW Qdg=0
16MW Qdg=00
200400600800
1.0001.2001.4001.6001.8002.000
Qs [kVAr]
16MW Qdg=1,4 koord.16MW Qdg=-0,616MW Qdg=013MW Qdg=0
7
0200400600800
1.0001.2001.4001.6001.8002.000
Qs [kVAr]
16MW Qdg=1,4 koord.16MW Qdg=-0,616MW Qdg=013MW Qdg=0
0200400600800
1.0001.2001.4001.6001.8002.000
Qs [kVAr]
16MW Qdg=1,4 koord.16MW Qdg=-0,616MW Qdg=013MW Qdg=0
22,00
22,22
22,44
22,66
22,88
Stasjon 2 4 6 8 10 12 14 16 18 20 km
Linjespenning - 2 MW last, 20 km FeAl120
16MW Qdg=0
16MW Qdg=-0,6
13MW Qdg=022,00
22,22
22,44
22,66
22,88
Stasjon 2 4 6 8 10 12 14 16 18 20 km
Linjespenning - 2 MW last, 20 km FeAl120
16MW Qdg=0
16MW Qdg=1,4 koord.
16MW Qdg=-0,6
13MW Qdg=0
Qs=0
Line voltage – 20 km feeder (FeAl 120), 2 MW load Reactive power flow into feeder:
Illustration – High generation & low load:
Coordinated
Frankfurt (Germany), 6-9 June 2011
Synchronous generators can easily contribute in voltage control Necessary in many networks Large flow of reactive power
Common strategies for reactive power generation: Qdg=0 High line voltages & Low losses Qdg<0 Low voltages & High losses & High Qs into feeder
Coordinated reactive power control is suggested when generation is high & consumption is low in many other frequently occurring operating situations Sub-station reactive power and current is reduced compared to Qdg<0 Active power generation can be increased compared to Qdg=0 with almost the same maximum line voltage as with Qdg<0Calculated loss reduction up to 20 % .... More efficient measures as line reinforcement can be postponed!
Paper conclusion: