Transmission grid planning

Due to inadequate network structures and aging equipment in existing transmission systems, the high demand for growth and generation expansion leads to bottlenecks and performance issues. The merging of more and more partial systems poses additional challenges. In order to increase the reliability and efficiency of transmission networks, Siemens PTI offers:

• ­Network concept for a phased development plan addressing increasing load and power quality requirements
• ­Definition of an aligned and sound system model for steady-state and dynamic calculations
• ­Review of load shedding schemes
• ­Distribution network concepts for large cities
• Training and management consulting

New generation units, such as highly efficient gas and thermal power plants, wind and photovoltaics (PV) farms, need to comply with the grid codes issued by system operators. Siemens PTI offers relevant studies for TSOs, power plant operators, investors and generation unit manufacturers:

• ­Assessing fulfillment of grid code compliance
• ­Grid planning review with increased renewable generation
• ­Feasibility and facility studies involving power flow, short circuit, transfer limits
• ­Dynamic stability analyses to define equipment requirements, e.g. converter-based infeeders
• ­Transient studies (switching, lightning, inrush studies)
• Identification and optimization of necessary investments
  

Every power system is subject to continuously changing conditions, both planned and unplanned. Therefore stability analyses are highly important for ensuring reliability of supply and avoiding outage costs. Siemens PTI performs detailed stability studies including:

• ­Analysis of transient stability, rotor angle stability, voltage stability, small signal stability, and frequency stability
• ­Design of controllers for power oscillation damping
• ­Simulation and analysis of the dynamic behavior of the system to identify relevant measures to improve system stability
• Determination of measures for ensuring safe and reliable operation, even at high loads

The importance of HVDC, long-distance interconnections and back-to-back couplings has increased significantly all over the world. Installing wind parks far from shore requires transporting large amounts of power over long distances where AC solutions are no longer possible or too expensive. Hybrid AC/DC concepts are also applied in island networks without own generation or generation with little share of synchronous machines. Siemens PTI is a key partner in planning new HVDC applications by providing:

• ­Assessment and verification of HVDC as a solution for long-distance power transmission with load flow and dynamic analyses
• ­Evaluation of solutions for network coupling and system stability improvement
• ­Analyses of the impact on frequency and voltage stability and definition of suitable control strategies
  
• Dynamic analyses of island networks with HVDC as main infeed and verification of black start capability 

• Simulating and analyzing SSR phenomena, e.g. by means of eigenvalue analysis, frequency analysis techniques and transient torque analysis
• Evaluation of possible countermeasures, such as:
  
  - avoidance of certain topology, bypass capacitors, reduced power generation, etc.
  
  - replacement of shaft components, transformers, series capacitors, etc.
  
  - passive or active control, monitoring of shaft stresses

Protection systems are crucial for system security because they limit the impact faults have on power systems. Continuously evolving power systems and quickly changing operating conditions make it a complex task to calculate, verify, and validate protection settings. Siemens PTI offers:

• ­Simulation of selectivity, sensitivity and speed of the protection system performance for different network and operation conditions
• ­Performing fast protection security assessments for reliable protection-setting determination
• Protection system improvement by rule-based correction of settings or system-wide optimizations of the protection settings

Measures taking into account the control of generation units, flexible loads and switching actions to guarantee high resilience and fast resupply.

Determining and dimensioning required momentary, short-term and long-term reserve power in order to maintain frequency stability and a stable power system.

Optimized utilization of network transfer capacities to avoid bottlenecks in the transmission system.

Measurements and system simulation to understand outages in power system operation and define suitable mitigation measures.

Analysis of interferences from power supply systems on other networks and systems, modeling and calculation of electromagnetic fields.

Modeling and analysis of overvoltages and other transient phenomena, as well as of switching actions and their impact on system performance.

Dimensioning of instrument transformers in substations and switchgear, especially current transformers in gas-insulated switchgear (GIS).

Evaluation of voltage stresses and determination of appropriate insulation levels and of protective devices for equipment and systems.

Optimizing generator ratings by using FACTS devices for fast reactive power support.

Measurements, development of lightning protection and grounding concepts, performance validation of installed systems and related disturbance analyses.

Innovative grid architecture and configuration considering latest technologies and communication infrastructure, as well as smart grid applications.

Measurement, evaluation and continuous monitoring of power quality related phenomena to avoid equipment failure.

Real time digital simulation of protection devices to understand operating principles of different devices and to optimize and verify setting values.

Design and monitoring of a customized regulatory compliance program and assistance during audits to avoid monetary penalties and reputational impact.

Technically and economically optimized voltage control concepts including selection and optimal placement of controllers.