Covering the fundamentals of electrical transients, this book should equip readers with the skills to recognise and solve transient problems in power networks and components. Starting with the basics of transient electrical circuit theory, and moving on to discuss the effects of power transience in all types of power equipment, it provides insight into this important field. Recent advances in measurement techniques, computer modelling and switchgear development are given comprehensive coverage for the first time. An electromagnetic transients calculation program is included and should prove valuable to both students and engineers in the field.

https://bib.convdocs.org/v10706/?download=1

Transients in Power Systems

Innovative Rogowski coils enable the design of advanced protection systems when used with new multifunction relays and fiberoptic communication. The protection systems have faster response times to faults and can easily adjust to load and/or power system configuration changes. Since the new Rogowski coils are very accurate and do not saturate, protection levels can be set to lower fault current thresholds, reducing the stress on the protected equipment. The whole system is immune to external magnetic fields and has self-testing logic. No wiring is necessary.

PCB Rogowski coils benefit relay protection

Protection systems for electrical systems such as substation power dividers are described. The protection systems may be designed and used to detect and clear faults that may occur within the substation power dividers. For example, a first Rogowski coil may be used to detect current along a primary conductor, and output a corresponding current signal to a multi-function, differential relay having multiple voltage and current inputs. Similarly, additional Rogowski coils may be used at each of a plurality of secondary feeders, where power from the primary feeder may be distributed to the secondary feeders using a connection bus. By comparing the signals from the first Rogowski coil and the additional Rogowski coils, the differential relay may determine whether a fault exists at some point along the conductor(s) and between the first Rogowski coils and the additional Rogowski coils, including whether a fault is associated with the connection bus. Further, the relay may then, in response to the fault, trip a circuit breaker or other network protection device, so that the fault may be corrected.

Electrical protection system

This paper investigates the effects of some influence quantities on the measurement of power frequency sinusoidal currents by means of flexible Rogowski coil sensors. The analysis is carried out through a numerical model, which is specifically developed and allows both the prediction of the circuital and coil parameter effects and the improvement of the coil design. The estimate of the measurement uncertainty associated with the on-site use of a flexible and openable Rogowski coil is finally given by assuming relatively controlled operating conditions.

Evaluation of Flexible Rogowski Coil Performances in Power Frequency Applications

Protection systems are described for electrical systems such as electrical arc furnaces. The protection systems may be designed and used to detect and clear faults that may occur within the electric arc furnace. For example, a pair of Rogowski coils may be used to detect current at their respective locations along a conductors, and output corresponding signals to a multi-function, differential relay having multiple voltage and current inputs. By comparing the signals from the Rogowski coils, the differential relay may determine whether a fault exists at some point along the conductors and between the pair of Rogowski coils. Further, the relay may then, in response to the fault, trip a circuit breaker or other network protection device, so that the fault may be corrected.

L. Kojovic

Papers

Rogowski coils suit relay protection and measurement