1-4
B90 Low Impedance Bus Differential System
GE Multilin
1.2 UR OVERVIEW
1 GETTING STARTED
1
c) UR SCAN OPERATION
The UR-series devices operate in a cyclic scan fashion. The device reads the inputs into an input status table, solves the
logic program (FlexLogic equation), and then sets each output to the appropriate state in an output status table. Any result-
ing task execution is priority interrupt-driven.
Figure 1–3: UR-SERIES SCAN OPERATION
1.2.3 UR SOFTWARE ARCHITECTURE
The firmware (software embedded in the relay) is designed in functional modules that can be installed in any relay as
required. This is achieved with object-oriented design and programming (OOD/OOP) techniques.
Object-oriented techniques involve the use of
objects
and
classes
. An object is defined as “a logical entity that contains
both data and code that manipulates that data”. A class is the generalized form of similar objects. By using this concept,
one can create a protection class with the protection elements as objects of the class, such as time overcurrent, instanta-
neous overcurrent, current differential, undervoltage, overvoltage, underfrequency, and distance. These objects represent
completely self-contained software modules. The same object-class concept can be used for metering, input/output control,
software interface, communications, or any functional entity in the system.
Employing OOD/OOP in the software architecture of the B90 achieves the same features as the hardware architecture:
modularity, scalability, and flexibility. The application software for any UR-series device (for example, feeder protection,
transformer protection, distance protection) is constructed by combining objects from the various functional classes. This
results in a common interface across the UR series.
1.2.4 IMPORTANT UR CONCEPTS
As described above, the architecture of the UR-series relays differ from previous devices. To achieve a general understand-
ing of this device, some sections of Chapter 5 are quite helpful. The most important functions of the relay are contained in
“elements”. A description of the UR-series elements can be found in the
Introduction to elements
section in chapter 5.
Examples of simple elements, and some of the organization of this manual, can be found in the
Control elements
section of
chapter 5. A description of how digital signals are used and routed within the relay is contained in the
Introduction to Flex-
Logic
section in chapter 5.
Summary of Contents for B90 UR Series
Page 316: ...A 4 B90 Low Impedance Bus Differential System GE Multilin A 1 PARAMETER LISTS APPENDIX A A ...
Page 406: ...B 90 B90 Low Impedance Bus Differential System GE Multilin B 4 MEMORY MAPPING APPENDIX B B ...
Page 436: ...C 30 B90 Low Impedance Bus Differential System GE Multilin C 7 LOGICAL NODES APPENDIX C C ...
Page 446: ...D 10 B90 Low Impedance Bus Differential System GE Multilin D 1 IEC 60870 5 104 APPENDIX D D ...
