DynaGridCenter – an innovative and future-oriented project
The German Ministry of Economic Affairs and Energy (BMWi) is supporting the innovative spirit of German-based companies by offering innovation-friendly conditions and market-oriented R&D and innovation activities. The DynaGridCenter project for the development of traditional transmission control centers into future-proof dynamic control centers is funded with roughly €5 million.
Intelligent grid controlEfficient management of system dynamics With the massive integration of renewable energy sources and power electronics, the control and monitoring of our transmission grids is becoming increasingly complex. In many countries, large nuclear or coal-fired power plants are taken off the grid and electrical energy needs to be transported over longer distances. This increases the potential for system instabilities in frequency and voltage. In order to avoid or eliminate such congestions and protect the installed equipment, the generating units haves to be actively managed and redispatched, leading to constantly increasing costs. A promising solution is to invest into intelligent control systems and digital substations control technology which reacts effectively and foresightedly to system dynamics.
In order to maintain the stability of our highly dynamic transmission grids, in the future we will require control centers with automated control functionality.Prof. Dr.-Ing. Rainer Krebs, Principal Expert and Head of System Protection Operation and Control Department, Division Energy Management, Siemens AG
Real-time simulation center in Magdeburg
A real-time software-based power-system simulator was installed at the Otto-von-Guericke University in Magdeburg for a reduced model of the German transmission network. The simulator is coupled with the power-electronics lab with HVDC hardware, resulting in a hybrid simulation. Protection and measuring components like relays and PMUs are forming together with substation automation and communication so-called digital substations.
Dynamic grid control center in Ilmenau
As main part of the project, a dynamic grid control center, based on Siemens Spectrum Power was installed at the Technical University of Ilmenau, 200 km away from the real time grid model in Magdeburg Newly developed dynamic applications are integrated as assistant systems for e.g. “Dynamic Security Assessment”, “Adaptive Protection Settings” and “PMU Data Streaming Analytics”, assessing the power system for time-now and for forecasted situations. Main task of these apps is to propose validated preventive or reactive measures to the operator.
The control center is connected to the digital substation models in Magdeburg. The grid model sends measured data to the control center via the digital substation models where the dynamic behavior is simulated and analyzed continuously in real time.
Project results at a glanceThe key idea of the project was to develop an innovative system control methodology on the high and ultra-high voltage levels based on the structure of existing control rooms. This methodology will allow for an adaptive integration of new, complex technologies into existing grid structures and enable grid operators to maintain high supply reliability in the future.
Scenario 1: Hardware in the loop
High-voltage direct current (HVDC) transmission lines will play an important role in future power transmission networks. These HVDC transmission lines transmit large amounts of energy over long distances within the existing alternating current (AC) network and, with the aid of power electronics, behave quite differently from conventional equipment. In order to be able to study this behavior, an HVDC line was built on a laboratory scale and integrated into a simulation of the AC grid (hardware-in-the-loop).
Scenario 2: Preventive HVDC measures
An HVDC line in the transmission network can be used as additional equipment to achieve an optimized operating point in terms of stability after equipment failures while avoiding expensive re-dispatch measures of power plants. The necessary changes to the HVDC operating point are regularly determined using new algorithms and verified using dynamic stability analyses before they are sent to the plant. This ensures that not only the thermal limits but also the stability limits are observed at all times.
Scenario 3: Corrective HVDC measures
With quickly controllable operating resources such as HVDCs or renewable feeders, bottlenecks can be eliminated when they actually occur. This presupposes that the necessary measures, i.e. changes in working points, are coordinated holistically and initiated and implemented with sufficient speed. Such behavior is called curative n-1. In the DynaGridCenter project, systems have been developed that use optimization algorithms (HEOneu), dynamic simulations (DSA) and highly dynamic local measurements to determine suitable corrective measures, which are then automatically executed in the field by the respective control unit. Similar to the preventive measures in scenario 2, the designed workflow ensures that neither the stability limits nor the thermal limits are exceeded at any time.
Szenario 4: Detection of defects (short circuits) in the grid
Similar to scenario 3, corrective measures should only be taken in case bottlenecks are expected to occur due to network failures or outages. The measures are verified beforehand by means of dynamic simulation (DSA). Impending bottlenecks are recognized by highly sophisticated machine learning algorithms which can compare real-time phasor measurements with simulated PMU measurements delivered by DSA. A reaction time of less than one second drastically reduces the current reaction time of manual central interventions.
Scenario 5: Simultaneous adaptation of parameters
The dynamic behavior of our electrical networks is significantly influenced by local control units. The controller parameters in a power plant, for example, are optimized in such a way that, from the grid's point of view, they behave system compliant at all possible operating points. Generally they are set once and are not adapted after that. If the parameters could be changed depending on the network situation, the system stability could be increased in many situations. In the Dyna Grid Center project, optimization algorithms have been developed to optimize all the controller parameters with respect to the current network status at regular intervals. These optimized parameters are then also verified using DSA. The dynamic control room is able to continuously communicate the optimized parameters to the relevant units via IEC 61850.