White Papers & Case Studies
Research is a core part of our business.
White Papers & Case Studies
Research is a core part of our business.
The need for high-speed multi-function protective relays in both traditional transmission systems and the new emerging paradigm of the smart grid is growing. As a widely used protective scheme for transmission lines, a distance relay’s high speed and reliable operation to clear faults is essential. This paper proposes a real-time low-latency hardware digital distance protective relay on the field programmable gate array (FPGA). Taking advantage
of inherent hard-wired architecture of the FPGA, the proposed hardware distance relay design is paralleled and fully pipelined to achieve low latencies in various relay modules which are developed in textual VHDL language. This low-latency feature allows fast operating and data throughput so that the relay can handle high-frequency sampled data and reach higher computational efficiency. In addition, the parallelism and hardwired architecture
of the FPGA makes the design more reliable in computation than the sequential software-based numeric relay. The FPGA-based distance relay can operate on both phasor-based signals and instantaneous signals with 2.09 and 0.35 latency respectively based on the clock frequency of 100 MHz. The hardware relay is tested in real-time by feeding it with generated faulted current and voltage data for typical faults and the relay response recorded. The results demonstrate the speed and effectiveness of the hardware distance relay.
The need for high-speed multi-function protective relays in both traditional transmission systems and the new emerging paradigm of the smart grid is growing. As a widely used protective scheme for transmission lines, a distance relay’s high speed and reliable operation to clear faults is essential. This paper proposes a real-time low-latency hardware digital distance protective relay on the field programmable gate array (FPGA). Taking advantage
of inherent hard-wired architecture of the FPGA, the proposed hardware distance relay design is paralleled and fully pipelined to achieve low latencies in various relay modules which are developed in textual VHDL language. This low-latency feature allows fast operating and data throughput so that the relay can handle high-frequency sampled data and reach higher computational efficiency. In addition, the parallelism and hardwired architecture
of the FPGA makes the design more reliable in computation than the sequential software-based numeric relay. The FPGA-based distance relay can operate on both phasor-based signals and instantaneous signals with 2.09 and 0.35 latency respectively based on the clock frequency of 100 MHz. The hardware relay is tested in real-time by feeding it with generated faulted current and voltage data for typical faults and the relay response recorded. The results demonstrate the speed and effectiveness of the hardware distance relay.
Two substation automation system (SAS) replacement projects operating with redundant IEC61850-8-1 station buses have been successfully commissioned and commenced commercial services. The City of Red Deer, a municipality with a population of about 100,000, collaborated closely with an engineering consultant and SA equipment vendor during various project milestones. This paper reviews and shares the benefits experienced and lessons learned from the design, execution, commissioning and operation perspectives of the two upgrade projects, paying close attention in particular to:
- Implementation of numerical intelligent electronic devices (IED) for versatile protection, automation and control (PAC) applications utilizing IEC61850 Generic Object Oriented Substation Event (GOOSE) and Manufacturing Message Specification (MMS) assisted communication features
- Application of parallel redundancy protocol (PRP) to achieve true network redundancy
- Benefits attained from factory acceptance and resulting expedited commissioning experience
- Lessons learned from the two digital substation experiences
The first substation upgraded had a main-tie-main air insulated bus arrangement, whereas the second one was a double-bus-single-breaker gas insulated switchgear (GIS) system. Each project lends its unique attributes to the discussion of the above listed points and will be referred to and compared with throughout the context of this paper.
Two substation automation system (SAS) replacement projects operating with redundant IEC61850-8-1 station buses have been successfully commissioned and commenced commercial services. The City of Red Deer, a municipality with a population of about 100,000, collaborated closely with an engineering consultant and SA equipment vendor during various project milestones. This paper reviews and shares the benefits experienced and lessons learned from the design, execution, commissioning and operation perspectives of the two upgrade projects, paying close attention in particular to:
- Implementation of numerical intelligent electronic devices (IED) for versatile protection, automation and control (PAC) applications utilizing IEC61850 Generic Object Oriented Substation Event (GOOSE) and Manufacturing Message Specification (MMS) assisted communication features
- Application of parallel redundancy protocol (PRP) to achieve true network redundancy
- Benefits attained from factory acceptance and resulting expedited commissioning experience
- Lessons learned from the two digital substation experiences
The first substation upgraded had a main-tie-main air insulated bus arrangement, whereas the second one was a double-bus-single-breaker gas insulated switchgear (GIS) system. Each project lends its unique attributes to the discussion of the above listed points and will be referred to and compared with throughout the context of this paper.
Over the past 5 years IEC 61850 has gained in popularity in various utilities across the globe for its promise of interoperability, scalability, maintainability and wire reduction. However the application and acceptance of this standard is still in its infancy in the province of Alberta, Canada. This paper presents a case study of one of the first substation automation projects applying the IEC 61850 standard in the province. The focus of this paper is not to discuss the theoretical background of the standard itself. Rather, the purpose is to share and demonstrate the engineering steps taken and lessons learned to successfully implement a fully functional protection and control system based around IEC 61850. The complete system developed for this project includes the following elements:
- 138/25kV distribution substation consisting of two power transformers and ten feeders.
- Integration of 17 IEC 61850 compliant intelligent electronic devices (IED) to perform both protection and control (P&C) functions.
- Substation local area network (LAN) using optical fiber for inter-panel communication and applying the parallel redundancy protocol (PRP) to achieve complete communication redundancy.
- New human-machine interface (HMIs) combining supervisory control and data acquisition (SCADA) and data gateway functionality within the real-time process database of the substation hardened computer.
The paper begins with a high-level overview of the substation configuration and its protection requirements. System automation concepts and apparatus control strategies using the IED and HMI/gateway are described. The specific steps used to engineer inter-IED communication via generic
object oriented substation events (GOOSE) and client/server reporting services via manufacturing message specification (MMS) are discussed in details. Next, the factory acceptance tests and site commissioning used to verify the correct operation of the system are described. The paper finishes with a
lessons learned section comparing this project with the traditional implementation.
Over the past 5 years IEC 61850 has gained in popularity in various utilities across the globe for its promise of interoperability, scalability, maintainability and wire reduction. However the application and acceptance of this standard is still in its infancy in the province of Alberta, Canada. This paper presents a case study of one of the first substation automation projects applying the IEC 61850 standard in the province. The focus of this paper is not to discuss the theoretical background of the standard itself. Rather, the purpose is to share and demonstrate the engineering steps taken and lessons learned to successfully implement a fully functional protection and control system based around IEC 61850. The complete system developed for this project includes the following elements:
- 138/25kV distribution substation consisting of two power transformers and ten feeders.
- Integration of 17 IEC 61850 compliant intelligent electronic devices (IED) to perform both protection and control (P&C) functions.
- Substation local area network (LAN) using optical fiber for inter-panel communication and applying the parallel redundancy protocol (PRP) to achieve complete communication redundancy.
- New human-machine interface (HMIs) combining supervisory control and data acquisition (SCADA) and data gateway functionality within the real-time process database of the substation hardened computer.
The paper begins with a high-level overview of the substation configuration and its protection requirements. System automation concepts and apparatus control strategies using the IED and HMI/gateway are described. The specific steps used to engineer inter-IED communication via generic
object oriented substation events (GOOSE) and client/server reporting services via manufacturing message specification (MMS) are discussed in details. Next, the factory acceptance tests and site commissioning used to verify the correct operation of the system are described. The paper finishes with a
lessons learned section comparing this project with the traditional implementation.
Current differential relaying is a powerful method for detecting faults in power system equipment. Differential relays typically operate on a restrained slope characteristic where they issue a trip if the differential current exceeds a settable percentage (the slope) of the restraint current. When selecting
this slope setting, a relay engineer must balance sensitivity against security. Unequal CT saturation is a security concern which can lead to misoperation of a differential relay for external faults. This paper develops a formula which relay engineers can use to select a secure slope setting for maximum restraint type relays based on the expected worst case CT saturation in their application.
Current differential relaying is a powerful method for detecting faults in power system equipment. Differential relays typically operate on a restrained slope characteristic where they issue a trip if the differential current exceeds a settable percentage (the slope) of the restraint current. When selecting
this slope setting, a relay engineer must balance sensitivity against security. Unequal CT saturation is a security concern which can lead to misoperation of a differential relay for external faults. This paper develops a formula which relay engineers can use to select a secure slope setting for maximum restraint type relays based on the expected worst case CT saturation in their application.
This paper presents a unique transformer protection design consisting of one conventional restraint differential function and one low impedance phase segregated differential function for a 450MVA, 240kV autotransformer. The phase segregated differential protection has the advantage of being immune to inrush current and imbalance current caused by a load tap changer. By combining the two differential elements and optimizing the settings, the dual differential protection has superior performance than conventional transformer differential protection.
The two differential elements were implemented inside one physical micro-processor based relay, which greatly reduced CT requirements, cable connections and panel wiring.
This paper presents a unique transformer protection design consisting of one conventional restraint differential function and one low impedance phase segregated differential function for a 450MVA, 240kV autotransformer. The phase segregated differential protection has the advantage of being immune to inrush current and imbalance current caused by a load tap changer. By combining the two differential elements and optimizing the settings, the dual differential protection has superior performance than conventional transformer differential protection.
The two differential elements were implemented inside one physical micro-processor based relay, which greatly reduced CT requirements, cable connections and panel wiring.
