Protection system studies

Tap into Siemens PTI protection experts’ knowledge and experience to develop reliable protection schemes for power systems of all sizes, including microgrids. Our services include the definition of required protection functions for transmission line, transformer, circuit breaker, generator and motor protection, and designing protection and control schemes for special applications such as series compensated lines. In addition, our protection experts can evaluate existing protection philosophies and practices at utilities and benchmark them against industry standards and best practices. The resulting gap analysis can help drive improvements and upgrades to the protection system. 

The objective of a protection system is to keep the power system stable by removing from service only those components that are subject to the disturbance, while leaving as much of the network as possible still in operation. Misoperation or non-operation of protective relays due to incorrect settings can lead to severe  personal injury, damage to electrical equipment and widespread power outages or blackouts. Siemens PTI’s protection consultants are highly experienced in performing the required calculations to determine the settings for all relevant protection functions based on utility-specific protection philosophies. We provide this service for transmission, distribution and industrial applications.

Protection sensitivity – the need to operate and trip immediately – is often at odds with protection selectivity – the ability to discriminate between conditions that require prompt operation and tripping, and those that require time-delayed or no operation. To assist the protection engineer in performing large-scale protection security assessments, Siemens PTI has developed an automated tool which comprehensively evaluates the selectivity, sensitivity and speed of the protection system’s performance for different network and operating conditions. The results of the assessment are presented in an easy-to-understand manner so that the protection engineer can focus his or her attention on resolving the protection settings issues and improving the reliability of the system.

Siemens PTI can support your PRC-027-1 compliance efforts by helping you develop a standardized protection philosophy, planning for short-circuit model development and maintenance, developing processes for exchanging network and protection data with neighboring utilities, automating the protection assessment process including creation of audit-ready documentation, and other related activities. We also support your NERC PRC compliance efforts for standards such as PRC-019, PRC-023, PRC-024, PRC-025, and PRC-026.

To understand the root causes of failures, often the knowledge of specialists in various fields of grid planning, such as protection, insulation coordination, system dynamics or operation, needs to be combined. The Siemens PTI team supports grid operators in data collection and verification, including analysis of reference events and on-site measurements. Based on detailed modeling, our consultants help to verify the root cause and validate proposed mitigation measures.

For special applications, Siemens PTI offers customer workshops to perform extensive hardware-in-the-loop tests to verify setting values of relays, measuring equipment and controllers in a real-time simulation environment. Supported by experienced Siemens PTI grid and protection experts, these workshops allow customers to expand their capabilities to operate the devices and analyze disturbances and protection responses.

The development of the digital protection technology and the introduction of gas insulated switchgear (GIS) have led to a paradigm change in current transformer (CT) and voltage transformer (VT) dimensioning. Given the limited space in GIS substations, the accuracy of the limiting factor plays an important role. Siemens PTI supports in optimizing VTs and CTs regarding both technical requirements of modern digital relays and economic aspects.   

A detailed protection study requires the development of an accurate model of the electrical power system (lines, generators, transformers, etc.) and the associated protection equipment and schemes (instrument transformers, relays, teleprotection schemes, etc.). Siemens PTI’s consultants are expert users of industry standard software tools such as PSS®CAPE and PSS®SINCAL, and can leverage this expertise to build and validate the model of your system. We can also recommend processes and practices for maintaining this model and integrating it into the larger utility-wide enterprise data structures.