Control and protection system and method for calculating a dynamic capacity of an HVDC system

Abstract

A control and protection system (9) for controlling and protecting components (7a, 7b, 7c, 7x) of an HVDC system (1), the control and protection system (9) being configured for receiving input data (15, 16), the input data comprising sensor data (15) for a component and forecast data (16) for operation of the HVDC system, calculating from the input data (15, 16), by using a physical model (8a, 8b, 8c, 8x ) for each of the components (7a, 7b, 7c, 7x), an individual dynamic capacity (20a, 20b, 20c) for each of the components (7a, 7b, 7c, 7x), and calculating an overall dynamic capacity (11) of the HVDC system (1) by combining the individual dynamic capacities (20a, 20b, 20c).

Description

[0001] P2023,1476 WO N / P230062WO01 March 24,2025 -1 - DescriptionControl and protection system and method for calcul ating adynamiccapacityofan HVDC systemThe present disclosure relates to an HVDC (high-vol tagedirect current) control and protection system and a methodfor calculating a dynamic capacity of an HVDC syste m.HVDC systems are becoming increasingly widespread w orldwidedue to the transition to renewable energy. For longdistances,HVDC linkshave lowerpowerlossesthan ACtransmission lines. In addition to that, HVDC conve rterstations can be used for actively controlling activ e andreactive power in the grid and thereby contribute t o bettergrid control. Since HVDC systems are costly for gri doperators, it is important to optimally utilize the ircapacity.Online estimation of dynamic capacity can be conduc ted toutilize overload capacity based on operational cond itions, asdisclosed in the publication by M. Langwasser, K. S chönleber,A. Wasserrab, M. Thiele and M. Liserre, "Online est imation ofdynamic capacity of VSC-HVdc systems - power system usecases,"ETG Congress2021,2021,pp.704-709.US 8228694 B2 discloses a converter station for a HVDCtransmissionsline,wherein an overload capability oftheconverter station is increased by determining a val ue of theactual temperature of a critical component and a va lue of theactual temperature of any media used to cool the cr iticalcomponent and calculating the present overload capa bility bya mathematicalmodel. P2023,1476 WO N / P230062WO01 March 24,2025 -2 -Embodiments of the disclosure relate to an improved controland protection system and an improved method for ca lculatinga dynamiccapacityofan HVDC system.According to a first aspect, a control and protecti on systemfor controlling and protecting components of an HVD C systemis configured for receiving input data, the input d atacomprising at least one of sensor data for a compon ent andforecast data for operation of the HVDC system, cal culatingfrom the inputdata,byusing a physicalmodelfor each of the components,an individualdynamiccapacityfor each of the components,and calculating an overalldynamic capacityof the HVDC system by combining the individual dyna miccapacities.The input data may comprise sensor data for a compo nent andforecast data for operation of the HVDC system. The sensordata may be sensor data for at least one of the com ponents.Itisalso possible thatthe sensordata comprises sensor data forallofthe components.Conventionally, a fixed capacity domain for an HVDC system isagreed on by a grid operator and a supplier. The gr idoperator guarantees that the HVDC system can be saf elyoperated within this domain. However, the real capa city ofindividual components can vary over time, depending on real-time conditions, historic conditions and forecast c onditions.Also the capacity domain for different components o rdifferent types of components can vary in different ways overtime. By calculating an overall dynamic capacity fr omindividualdynamiccapacities,such variationscan be taken P2023,1476 WO N / P230062WO01 March 24,2025 -3 -into account and the full capability of the HVDC sy stem canbe used. Asan example,the componentsare selected from at leastoneof the types of a converter valve, a transformer an d a DCcable. The components considered for the calculatio n may beof different types. It is also possible that at lea st some ofthe components are from the same type. The componen ts may belocated in or near a converter station. Also compon ents fromdifferent converter stations can be considered in t hecalculation.Each of the individual dynamic capacities and the o veralldynamic capacity may be in the form of a capacity d omain ofactive and reactive power. It is also possible that a dynamiccapacity may be calculated as a limit for other par ameterssuch ascurrentflow in the system.The overall dynamic capacity can be calculated as a nintersection ofthe individualdynamiccapacities. Theoverall capacity domain can thus be limited by diff erentcomponents in different regions of the capacity dom ain.The control and protection system may be configured to enablesetting any setpoint of operation of the HVDC syste m withinthe boundariesofthe overalldynamiccapacity.Inparticular, also setpoints may be set which are out side apre-set fixed capacity domain defined by a grid ope rator, aslong asthe setpointsare within the boundariesof theoverall dynamic capacity. Thereby, grid congestions can beresolved and / or stabilization of the grid can be pr ovided. Asan example, a setpoint may comprise setting current and / orpowerflow in the HVDC system. P2023,1476 WO N / P230062WO01 March 24,2025 -4 - Furthermore,the controland protection system may beconfigured to set alert levels for the components o n thebasis of the individual dynamic capacities and / or t he overalldynamic capacity. As an example, an alert level may comprisesetting a maximum allowed current or temperature fo r acomponent.The control and protection system may be configured toprovide the overall dynamic capacity to an operator controlsystem. The operator control system may be remote f rom thecontrol and protection system. As an example, the c ontrol andprotection system or parts thereof may be located i n one ormore converter stations. The operator control syste m may belocated in a different building and a remote locati on. Theoperator control system may comprise a human machin einterface. In the operator control system, a setpoi nt foroperation of the HVDC system may be set, by using t he overalldynamic capacity provided by the control and protec tionsystem.The input data may comprise sensor data of at least one ofcurrent flowing through one of the components, a te mperatureof one of the components and ambient temperature at thelocation of one of the components. As an example, atemperature may be a hot-spot temperature or top-oi ltemperature ofa transformer,forexample.The sensor data may be live sensor data and / or hist oricsensor data. As an example, sensor data for a times panreaching from a past time to live operation time ma y beprovided.Asan example,sensordata from the last houror P2023,1476 WO N / P230062WO01 March 24,2025 -5 - severallasthoursmaybe provided.Asan example, a loading overthe lasthourmaybe provided.The forecast data may comprise grid operation plann ing and / ora forecast of weather conditions. As an example, gr idoperating planning may include a forecast of active and / orreactive power demands. Ambient conditions may incl ude aforecastofthe temperature atthe location ofthe componentsand / or a forecast of weather conditions relevant fo rrenewable energy. The calculated dynamiccapacitymaybe valid fora futuretime. The calculated dynamic capacity may be calcul ated forone or more hours or days in advance. Thereby, oper ationplanning is enabled. In particular, the dynamic cap acity maybe calculated for the time of the forecast data. It is alsopossible that the dynamic capacities are calculated to bevalid instantaneously. This allows reacting to sudd enly hightransmission need orload changes,forexample.The control and protection system may be configured to repeatthe calculation. As an example, the calculation may beautomatically repeated or on demand, e.g. by an ope rator. Thecalculation may be repeated every few minutes, hour ly ordaily. New input data may be provided for each repe tition. Asan example, updated sensor data and / or updated fore cast datamay be provided.According to a further aspect, a control system com prises acontrol and protection system and an operator contr ol system.The control and protection system may have any func tional andstructural characteristics as disclosed in the fore going. The P2023,1476 WO N / P230062WO01 March 24,2025 -6 -control system and the control and protection syste m areconfigured to communicate with each other.The control and protection system may be configured toprovide the calculated overall capacity to the oper atorcontrol system. The calculated overall capacity may betransmitted everytime the calculation isupdated. The operatorcontrolsystem maybe configured to seta setpointof operation within the boundaries of the overall d ynamiccapacity.The operator control system may be configured to pr ovide atleast a part of the input data to the control and p rotectionsystem. As an example, forecast data such as grid o perationplanning or weather forecast data may be provided b y theoperatorcontrolsystem.According to a further aspect, a method for control ling andprotecting components of an HVDC system comprises t he stepsofreceiving inputdata,the inputdata comprising atleastone of sensor data for a component and forecast dat a foroperation ofthe HVDC system,calculating from the inputdata, by using a physical model for each of the com ponents,an individual dynamic capacity for each of the comp onents,and calculating an overalldynamiccapacityofthe HVDCsystem by combining the individual dynamic capaciti es. Themethod may carry out any steps and may comprise anyfunctional and structural characteristics as disclo sed in theforegoing for the control and protection system and thecontrolsystem.The method may be a computer-implemented method. Th e methodmay be carried out by the control and protection sy stem and P2023,1476 WO N / P230062WO01 March 24,2025 -7 - / or the control system as disclosed in the foregoin g.However, the method may be also carried out by a di fferentsystem.The method steps may be conducted locally or remote ly. One ormore of the method steps may also be conducted with in a cloudsystem.The method may comprise the further step of setting asetpoint of operation of the HVDC system within theboundaries of the overall dynamic capacity. In part icular, asetpoint may be set which is outside a pre-set fixe d capacitydomain defined by a grid operator, as long as the s etpointsare within the boundaries of the overall dynamic ca pacity.The method may comprise the further step of setting alertlevels for the components on the basis of the indiv idualdynamic capacities and / or the overall dynamic capac ity.As disclosed above in connection with the descripti on of thecontroland protection system,the calculation may berepeated, either automatically or on demand. The ca lculationmay be repeated at regular time intervals. The inpu t data maybe updated at least partially for each new calculat ion. Theoverall dynamic capacity may be valid instantaneous ly or fora future time.The present disclosure comprises several aspects an dembodiments. Every feature described with respect t o one ofthe aspects and embodiments is also disclosed herei n withrespectto the otheraspectsand embodiments,even iftherespective feature is not explicitly mentioned in t hiscontext. P2023,1476 WO N / P230062WO01 March 24,2025 -8 -Further features, refinements and expediencies beco meapparent from the following description of the exem plaryembodimentsin connection with the figures.In the figures,elements of the same structure and / or functionality may bereferenced by the same reference signs. It is to beunderstood that the embodiments shown in the figure s areillustrative representations and are not necessaril y drawn toscale.Figure 1 shows an HVDC system in a schematic diagra m,Figure 2 showscapacitydomainsand setpointsin a schematic diagram,Figure 3 shows an embodiment of a control and prote ctionsystem and method steps for calculating a dynamic c apacity ina schematicdiagram,Figures 4A to 4C show individual capacity domains f ordifferent components of the HVDC system in a schema ticdiagram,Figure 5A shows a combination of the individual cap acitydomains of Figs. 4A to 4C to an overall capacity do main,Figure 5B shows the overall capacity domain as obta ined inFig.5A,Figure 6 shows an interaction of an HVDC control an dprotection system and a network control system in a schematicdiagram. P2023,1476 WO N / P230062WO01 March 24,2025 -9 -Figure 1 shows an HVDC system 1 comprising DC trans missionlines2,which can be used forlong distance power transmission.Atthe end ofthe transmission lines 2 converterstations3,4 are located forconverting AC current in AC grids5,6 to DC currentorvice versa.A converter station 3, 4 may function as a rectifie r tocovert AC current into DC current or as an inverter toconvert DC current into AC current. The converter s tations 3,4 may be configured to be switched between a rectif ier modeand an inverter mode to control flow of electric po wer inboth directions. The HVDC system 1, and in particul ar theconverter stations 3, 4 comprise several components ,including convertervalves7a,transformers7b and DC cables7c. The DC cable 7 may connect components in the co nverterstations 3, 4. The components can be also at differ entlocations than the converter station 3.A control and protection system 9 controls and prot ects theHVDC system 1, in particular the components. The co ntrol andprotection system 9 may comprise a computer and a s oftwareinstalled on the computer to control the HVDC syste m 1. Thecontrol and protection system 9 may be a local syst em and maycomprise a processing device located in one of or e ach of theconverter station 3, 4. It is also possible that th e controland protection system 9 is a remote system and conn ected tothe converterstations3,4 bya suitable network. Itisalsopossible that the protection and control system 9 i sintegrated in a SCADA system.The control and protection system 9 ensures that th e HVDCsystem 1 and, in particular, the components are onl y operatedwithin the boundaries of an allowed capacity domain . P2023,1476 WO N / P230062WO01 March 24,2025 -10 -Figure 2 shows capacity domains 10, 11 in a P / Q-Dia gram,wherein P denotes the active power and Q denotes th e reactivepower. P is given in megawatts and Q is given in Me gavolt-amperesreactive.A capacity domain 10, 11 defines the boundaries for operatingsetpoints of active power P and reactive power Q. U sually, agrid operator gives guarantees, as long as the HVDC system 1is operated within the boundaries of the capacity d omain 10,11. The guarantees are, e.g., a performance guarant ee,dynamic performance, harmonics, guaranteed lifetime ,maintenance periods, etc. The capacity domain 10, 1 1 isusually given for a maximum operating ambient tempe rature,e.g.,40 °C in Europe. Conventionally,the P / Q capacitydomain isa fixed capacitydomain 10, which is agreed on by a grid operator an d asupplier. The grid operator guarantees that the HVD C system 1can be safely operated within this domain 10. The f ixedcapacity domain 10 usually has the shape of a recta ngle inthe P / Q plane, which may differ between the power f lowdirection, i.e., between an inverter or rectifier m ode.The fixed capacity domain 10 does not change over t ime. Thecontrol and protection system 9 always respect this fixedcapacitydomain 10 so thata setpoint12 isalways within the boundariesofthisdomain 10.An operation outside the fixed capacitydomain 10 isnotforeseen,asitmaylead to equipmentfailuresoraccelerated equipmentaging.SCADA (supervisory control and data acquisition) sy stemsutilize the guaranteed capacitydomain 10 asfixed boundariesfor variables. The SCADA system may be a network sy stem. P2023,1476 WO N / P230062WO01 March 24,2025 -11 - Reportsregarding the inherentoverload ofan HVDC system 1can be generated and shared with customers upon req uest, e.g.in tenders. The controland protection system 9 ofthe present invention,however, calculates a dynamic capacity domain 11. T he dynamiccapacity domain 11 takes into account that the actu alinherentcapacityofthe HVDC system 1 varieswith changingoperating conditions. As an example, low ambient te mperature,reduced reactive power needs or favorable AC voltag econditions may be operational conditions where over loadcapabilities can be used. Such conditions allow set tingsetpoints outside a fixed capacity domain 10. The d ynamiccapacity domain 11 varies over time. As an example, thedynamic capacity may depend on the conditions, such asambient temperature and voltage at the point of com moncoupling (PCC) after a specific time of overload, e .g. onehouroverload.Depending on the conditions of past, present and ex pectedoperation,the dynamiccapacitydomain 11 can besignificantly larger than the fixed capacity domain 10. Thefixed capacity domain 10 is fully enclosed by the d ynamiccapacity domain 11. The HVDC system 1 can then be o perated ata specific time or time range, for which the dynami c capacitydomain 11 is valid, at every setpoint within the dy namiccapacity domain 11, e.g., also at a setpoint 13 out side thefixed capacity domain 10. In particular, the HVDC s ystem 1may be operated with higher currents and / or voltage s and,subsequently, at higher values for active power P a ndreactive power Q. In other words, by a dynamic capa citydomain 11, unused potential of the HVDC system 1 ca n beutilized. P2023,1476 WO N / P230062WO01 March 24,2025 -12 -Figure 3 shows an embodiment of an HVDC control andprotection system 9. The HVDC control and protectio n system9,in particularthe software package,comprisesa dynamiccapacity calculation module 14, which calculates in dividualdynamiccapacitiesforeach ofseveralcomponents. Thecalculation is based on a physical model 8a-8x of e ach of thecomponents stored in the HVDC control and protectio n system9. The physical model may be a digital twin or anot her modelofthe component'sstatusand behavior.A first component may be a converter valve 7a, a se condcomponent may be a transformer 7b, a third componen t may be aDC cable 7c, for example. The calculation can be ex tended tofurthercomponents7x,asshown in Fig.1.The physical model receives as a first input sensor data 15and as a second input forecast data 16. The input c an beprovided by the same input channel or different inp utchannels. Sensor data 15 may be live sensor data. I t is alsopossible that the sensor data 15 comprises historic sensordata. The sensor data 15 may also comprise estimate d datasuch as an estimated temperature. As an example, in case of atransformer, the estimated temperature may be a hot -spottemperature.The sensor data 15 and forecast data 16 may compris e datafrom the point of common coupling (PCC), i.e. the locationwhere the HVDC system connects to the AC grid or ne twork.This may be the location of one of the converter st ations 3,4 and / ortransformersand filtersatthe converter stations 3,4.The sensordata 15 maycomprise ambientdata such asambient temperature. The sensor data 15 may compris e a P2023,1476 WO N / P230062WO01 March 24,2025 -13 - voltage levelatthe PCC,in particularan AC grid voltage.The sensor data 15 may also comprise data on loadin g, activeand / orreactive poweroperation points.The forecast data 16 may comprise a forecast of the datameasured by the sensors. As an example, the forecas t data 16may comprise ambienttemperature and / orvoltage at PCC.Theforecast data 16 may comprise other data, such as a forecastofan overload duration. Both sensordata 15 and forecastdata 16 varyover time.Thedata 15, 16 may be provided continuously at regularintervals. As an example, data of the first input 1 5 may beprovided every 10 minutes. Data of the second input 16 may beprovided every hour. It is also possible that the t imeintervals for some of the data types are different.For each of the components, an individual dynamic c apacitydomain is calculated from the first input 16 and th e secondinput 16 by using the individual physical models 8a -8x of thecomponents. From the individual dynamic capacity do mains, anoverall dynamic capacity domain for the HVDC system 1 iscalculated,which isatleasta partofthe output 18 ofthedynamic capacity calculation module 14. The individ ualcomponents can have dynamic limits with different p hysicalquantities. As an example, currents depending on po werangles,active and / orreactive power.The calculated overall dynamic capacity domain is p rovided tothe setpoint calculation module 17. Also the indivi dualcapacity domains 18 can be provided to the setpointcalculation module 17. Additionally, the overall dy namiccapacity domain can be provided for system operatio n, i.e. a P2023,1476 WO N / P230062WO01 March 24,2025 -14 -grid control, so that any P / Q setpoint within the d omain canbe selected manuallyorautomatically. The setpointcalculation module 17 then calculates from theoverall setpoints individual setpoints for the comp onents 7a-7x such that the overall setpoint is within the bou ndaries ofthe overall dynamic capacity domain. The individual setpointsare the output19 ofthe calculation module 17 and the entirecontrol and protection system 9. As an example, ind ividualsetpoints may comprise setting limits of voltage an d currentforindividualcomponents.Furthermore,a setpoint maycomprise setting operating voltages and currents fo rindividualcomponents.The controland protections system 9may set alert levels based on the calculated capaci tydomains.The control and protections system 9 may transmit t he overalldynamic capacity to an operator control system, whe rein asetpointissetin the operatorcontrolsystem and the setpointand / orlimitsforthe componentsare thantransmitted back to the control and protection syst em 9.The dynamic capacity can be used, e.g., for transmi tting morepower for a certain time duration than would be pos siblewithin a fixed capacity domain, for congestion mana gement,forvoltage control,etc.Figures 4A to 4C show individual capacity domains f ordifferent components of an HVDC system 1 in schemat icdiagrams. The individual capacity domains can be ca lculatedby the simulation models 8a-8x for the different co mponents7a-7x in the control and protection system 9 as sho wn inFigs.1 and 3,forexample. P2023,1476 WO N / P230062WO01 March 24,2025 -15 -The individual capacity domains 20a, 20b, 20c may b ecalculated fora convertervalve 7a,a transformer 7b and aDC cable 7c, for example. The individual capacity d omains20a,20b,20chave differentboundariesdue to the differencesforthe components7a,7b,7c.Furthermore, the individual capacity domains 20a, 2 0b, 20cvary over time, depending on historic and / or live a mbientconditions or operating conditions of the component s 7a, 7b,7c.As an example, the size and shapes of each of the i ndividualcapacity domains 20a-20c depends on ambient conditi ons suchas ambient temperature and operating conditions suc h asvoltage atthe common pointofcoupling and active andreactive power demand. In particular, live conditio ns,historic conditions and forecasted conditions may d eterminethe individualcapacitydomains20a,20b,20c.As an example, the operating conditions over the la st fewhoursmaybe relevantfordetermining the capacity domains20a-20c. Furthermore, forecasted data for grid oper ationplanning maybe an inputinto the calculation.The forecasteddata may include ambient conditions and operating c onditionssuch as a forecast of active and reactive power dem ands.The calculation may be repeated with at least parti allyupdated data at pre-defined intervals, e.g. every 5 minutes.Figure 5A shows combining the individual dynamic ca pacitydomains 20a-20c of Figs. 4A to 4C to an overall dyn amiccapacitydomain 11. P2023,1476 WO N / P230062WO01 March 24,2025 -16 - The overalldynamiccapacitydomain 11 isobtained from thecommon intersection area of all individual capacity domains20a-20c.In otherwords,everysetpointwithin the boundariesof the overall capacity domain 11 is also a setpoin t withineach of the boundaries of the individual capacity d omains20a-20c. The overall capacity domain 11 might be th us limitedby different components in different regions of the capacitydomain.The arrowsshow example powerangelswhere differentindividual capacity domains 20a-20c are the limitin g ones.Figure 6 shows a control system 22 comprising an op eratorcontrolsystem 21 communicating with a controland protectionsystem 9 for dynamic capacity calculation. The cont rol andprotection system 9 maybe asshown in Fig.3,for example. The overallHVDC system 1 maybe controlled bythe operatorcontrol system 21, which may be a SCADA system, for example.The operator control system 21 may have a human-mac hine-interface,which allowsmonitoring and / oractivelycontrolling the HVDC system 1 by a grid operator. T heoperator control system 21 may be a local system, a ttributedto one ormore converterstations3,4 ormaybe a remote system.The operatorcontrolsystem 21 maybe also used for controlling severalconverterstations3,4 and / or several HVDC systems1.The operatorcontrolsystem 21 may comprise acontrol software running in a grid operator control room, forexample. The operator control system 21 may be a ne tworkcontrolsystem.The operator control system 21 may sent the input d ata, e.g.forecast data 16 to the control and protection syst em 9. Asan example, operation planning data including a req uired P2023,1476 WO N / P230062WO01 March 24,2025 -17 -capacity for a specific time, forecasting data, suc h asweatherdata and projected voltage profilesmaybe providedby the operator control system 21. As an example, t he datamay be sentatregularintervals,such asevery15 minutes.The control and protection system 9 may further inp ut data,e.g. sensor data 15, from local sensors. As an exam ple, thefirst input data 15 may include at least one of amb ienttemperature and voltage atthe OCC.The control and protection system 9 may run locally in aconverterstation 3,4.The controland protection system 9may calculate the individual dynamic capacity domai ns 20a-20cand the overall dynamic capacity domain 11. The dyn amiccapacity domain can be in the form of a P / Q diagram .Alternatively, the dynamic capacity domain may be i n the formof circuit current limitation, for example. It is a lsopossible that the operator control system 21 calcul ates theoveralldynamiccapacitydomain 11.The control and protection system 9 transmits the o utput 18,e.g. the calculated overall dynamic capacity domain 11 and / orthe individual capacity domains 20a-20c to the oper atorcontrolsystem 21.The operator control system 21 uses the dynamic cap acitydomains 11, 20a-20c for its grid control algorithms . Bysetting setpoints which are outside a fixed capacit y domain,the use of the HVDC systems capabilities can be opt imized.As an example, more options are available for the g ridoperatorto resolve grid congestionsand stabilize the grid.As an example, more power can be transmitted than a llowed P2023,1476 WO N / P230062WO01 March 24,2025 -18 - within the boundariesofa fixed,pre-setcapacity domain.Thereby, a curtailment by redispatching renewable e nergiescan be avoided, leading to a more cost efficient an dsustainable grid operation.

[0002] P2023,1476 WO N / P230062WO01 March 24,2025 -19 -Reference Signs1 HVDC system 2 DC transmission line 3 converterstation 4 converterstation 5 AC grid 6 AC grid 7a convertervalve 7b transformer 7c DC cable 7x furthercomponent 8a convertervalve model 8b transformermodel 8c DC cable model 8x furthercomponentmodel 9 controland protection system 10 fixed capacitydomain 11 dynamiccapacitydomain 12 setpoint 13 setpoint 14 dynamiccapacitycalculation module 15 sensordata 16 forecastdata 17 setpointcalculation module 18 outputofdynamiccapacitycalculation module) 19 outputofcontroland protection system) 20a individualcapacitydomain 20b individualcapacitydomain 20c individualcapacitydomain 21 operatorcontrolsystem 22 controlsystem P active power Q reactive power

Claims

P2023,1476 WO N / P230062WO01 March 24,2025 -20 - Claims1. A control and protection system (9) for controll ing andprotecting components (7a, 7b, 7c, 7x) of an HVDC s ystem (1),the control and protection system (9) being configu red forreceiving input data (15, 16), the input data compr isingsensordata (15)fora componentand forecastdata (16)for operation ofthe HVDC system, calculating from the inputdata (15,16),byusing a physicalmodel (8a, 8b, 8c, 8x) for each of the components ( 7a, 7b,7c,7x),an individualdynamiccapacity(20a,20b, 20c)for each ofthe components(7a,7b,7c,7x),and calculating an overall dynamic capacity (11) of the HVDCsystem (1) by combining the individual dynamic capa cities(20a,20b,20c). 2.The controland protection system claim 1,wherein the components (7a, 7b, 7c, 7x) are selecte d from atleast one of the types of a converter valve, a tran sformerand a DC cable. 3.The controland protection system ofanyofthe precedingclaims, wherein the individual dynamic capacities ( 8a, 8b,8c, 8x) and the overall dynamic capacity (11) are i n the formofa capacitydomain ofactive and reactive power. 4.The controland protection system ofanyofthe precedingclaims, wherein the overall dynamic capacity (11) i s anintersection of the individual dynamic capacities ( 20a, 20b,20c). 5.The controland protection system ofanyofthe precedingclaims, being configured to enable setting any setp oint ofP2023,1476 WO N / P230062WO01 March 24,2025 -21 -operation of the HVDC system (1) within the boundar ies of theoveralldynamiccapacity(11). 6.The controland protection system ofanyofthe precedingclaims, wherein the sensor data (15) comprises at l east oneof current flowing through one of the components (7 a, 7b, 7c,7x), a temperature of one of the components (7a, 7b , 7c, 7x)and ambient temperature at the location of one of t hecomponents(7a,7b,7c,7x). 7.The controland protection system ofanyofthe precedingclaims, wherein the sensor data (15) comprises live sensordata and / orhistoricsensordata. 8.The controland protection system ofanyofthe precedingclaims, wherein the forecast data (16) comprises gr idoperation planning and / or a forecast of weather con ditions.9.The controland protection system ofanyofthe preceding claims,being configured to repeatthe calculation at differenttimeswith updated inputdata (15,16).

10. The control and protection system of any of the precedingclaims, wherein the dynamic overall capacity (11) i scalculated to be valid ata future time.

11. A control system (22) comprising the control an dprotection system (9) of any of the preceding claim s andfurther comprising an operator control system (21), whereinthe control and protection system (9) is configured toprovide the calculated overall capacity (11) to the operatorcontrolsystem (21).P2023,1476 WO N / P230062WO01 March 24,2025 -22 - 12.The controlsystem (22)ofclaim 11,wherein the operator control system (21) is configu red to seta setpoint of operation within the boundaries of th ecalculated overallcapacity(11).

13. The control system (22) of any of claims 11 and 12,wherein the operator control system (21) is configu red toprovide atleasta partofthe inputdata (15,16) to the controland protection system (9).

14. A method for controlling and protecting compone nts of anHVDC system (1), the method comprising the steps ofreceiving input data (15, 16), the input data compr isingsensordata (15)fora componentand forecastdata (16)for operation ofthe HVDC system, calculating from the inputdata (15,16),byusing a physicalmodel (8a, 8b, 8c, 8x) for each of the components ( 7a, 7b,7c,7x),an individualdynamiccapacity(20a,20b, 20c)for each ofthe components(7a,7b,7c,7x),and calculating an overall dynamic capacity (11) of the HVDCsystem (1) by combining the individual dynamic capa cities(20a,20b,20c). 15.The method ofclaim 14,comprising the further step of setting a setpoint ( 12, 13) ofoperation for the HVDC system (1), the setpoint (12 , 13)being within the overalldynamiccapacity(11).

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