Reactive Power without coal

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Lights get turned on in the evening, as do many ovens, wash­ing machines and tele­vi­sions. If, at the same time, mass­es of elec­tric cars are con­nect­ed to the mains, volt­age can plum­met. Or it jumps through the roof when a lot of renew­able ener­gy pro­duc­ers pump green ener­gy into the grid in good weath­er. Until now, this was the time for fos­sil and nuclear pow­er plants, which flex­i­bly bal­anced out volt­age fluc­tu­a­tions using reac­tive pow­er. With their dis­con­tin­u­a­tion and the expan­sion of renew­ables, which ensure more volatil­i­ty in the grid, this indis­pens­able job is becom­ing vacant.

How­ev­er, one can­di­date for the vacan­cy has already proven itself: the “Mechan­i­cal­ly Switched Capac­i­tor with Damp­ing Net­work” or MSCDN tech­nol­o­gy. These five let­ters stand for an inno­v­a­tive plant that works with a mechan­i­cal­ly switched capac­i­tor bank includ­ing a damp­ing net­work. “In the future, MSCDN sys­tems will be increas­ing­ly need­ed to pro­vide capac­i­tive reac­tive pow­er or com­pen­sate volt­age fluc­tu­a­tions. They improve volt­age qual­i­ty and damp­en res­o­nances in the grid; and they also work effi­cient­ly and require lit­tle main­te­nance,” explains Uwe Jäger, Direc­tor Busi­ness Area Sub­sta­tions at Omex­om.

Sechtem: Fit for more grid power

MR’s Pow­er Qual­i­ty divi­sion and Omex­om Umspan­nwerke GmbH have fur­ther devel­oped MSCDN for demand­ing high and extra-high volt­age trans­mis­sion grids, and sub­sta­tions of three of the four Ger­man trans­mis­sion sys­tem oper­a­tors are already work­ing with it. In April of this year, the part­ners con­nect­ed a GRIDCON® MSCDN sys­tem for 380-kilo­volt elec­tric­i­ty to the grid at the Sechtem site of the oper­a­tor Ampri­on. The sub­sta­tion in the Born­heim dis­trict between Cologne and Bonn is an impor­tant hub where var­i­ous line cor­ri­dors meet — a favor­able loca­tion for grid con­trol.

“With the MSCDN plant, we are meet­ing the increased demands on the elec­tric­i­ty grid. We are absorb­ing the dis­man­tling of the coal-fired pow­er plants in the Rhineland and the demand for reac­tive pow­er, which is also increas­ing due to the grow­ing num­ber of tran­sits in the trans­mis­sion grid,” says Dr. Daniel Eich­hoff to jus­ti­fy the mil­lion-Euro invest­ment. The Head of the Sta­tions Depart­ment at Ampri­on is sat­is­fied with the result: “The sys­tem has been work­ing very reli­ably since com­mis­sion­ing and the coop­er­a­tion with MR and Omex­om was char­ac­ter­ized by a high degree of trust and an open, trans­par­ent exchange. We already know and val­ue each of the com­pa­nies as reli­able part­ners from pre­vi­ous projects.”

Further MSCDN plants by 2030

The MSCDN sys­tem is a com­po­nent of the mod­ern­iza­tion that has been under­way in Sechtem for sev­er­al years, and fits into the sophis­ti­cat­ed mix of sta­t­ic and dynam­ic com­pen­sa­tion mea­sures.  The sta­t­ic tech­nol­o­gy, which can be switched either on or off, reg­u­lates the base load. “This applies to the MSCDN sys­tem, which boosts volt­age, as well as to volt­age-reduc­ing choke coils that work with pow­er­ful tap chang­ers from MR,” explains Eich­hoff.

Dynam­ic sys­tems such as STATCOM (pow­er con­vert­ers) and rotat­ing phase shifters con­tin­u­ous­ly and flex­i­bly reg­u­late the remain­ing, tem­porar­i­ly chang­ing load. In addi­tion to the ren­o­va­tion of the entire sub­sta­tion in Sechtem, new trans­form­ers were also installed there to cope with the ener­gy tran­si­tion and the grow­ing demand for elec­tric­i­ty. Ampri­on uses a com­pre­hen­sive trans­former mon­i­tor­ing sys­tem to mon­i­tor, renew and expand its trans­former fleet. Growth is not only cer­tain at this point, announces Dr. Eich­hoff: “The MSCDN sys­tem in Sechtem was not our first and not our last. Two more are under con­struc­tion and we are plan­ning sev­er­al more at Ampri­on sites by 2030.”