Intelligent Electronic Device Fast Bus Transfer Synchronization
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Solution Overview
Problem
In industrial power systems, achieving fast and efficient transfer of loads from a failing source to a standby source is challenging due to synchronization issues, particularly with induction motors, as the phase angle drifts out of sync, and there is often insufficient time for reconnection before significant voltage and frequency differences occur, leading to mechanical shocks and heavy starting current surges.
Innovation Solution
The method involves using an Intelligent Electronic Device (IED) to monitor power supply parameters and proactively apply phase shifting or voltage corrections to synchronize power supplies, allowing for earlier reconnection by manipulating phase angles and voltage magnitudes, thereby increasing the chances of successful transfer within a shorter time frame, even when local control over speed, frequency, and voltage is not available.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If fast transfer is attempted by waiting for phase coincidence, then reconnection time is reduced, but synchronization reliability deteriorates due to phase angle drift and voltage/frequency differences
Solution Approach 1:
The system proactively modifies phase angles and voltage magnitudes before the actual reconnection occurs. By anticipating the synchronization needs and pre-adjusting the standby source parameters, the system ensures that when reconnection happens, the phase coincidence condition is already satisfied, thus reducing reconnection time while maintaining synchronization reliability.
Solution Approach 2:
The invention actively changes the parameters of the standby power source, specifically adjusting its phase angle and voltage magnitude to match the load bus conditions. This parameter modification allows the system to achieve synchronization faster and more reliably by controlling the phase difference and voltage match between sources.
2Reliability
If reconnection is delayed to ensure synchronization, then synchronization reliability improves, but loss of time increases due to motor slowdown and voltage collapse
Solution Approach 1:
The system performs preliminary adjustment of the standby source parameters before reconnection is needed. By proactively setting the phase angle and voltage magnitude to appropriate values, the system eliminates the need to wait for natural phase coincidence, thus reducing the time delay while ensuring synchronization reliability is maintained.
Solution Approach 2:
The invention replaces the passive mechanical waiting for phase coincidence with an active electronic control system that uses sensors and actuators to deliberately adjust and match phase angles and voltages. This substitution of active control for passive waiting dramatically reduces synchronization time while maintaining reliability.
3Speed
If phase shifting or voltage correction is applied proactively, then synchronization speed improves, but device complexity increases due to additional components
Solution Approach 1:
The system uses a multi-functional control device that can perform multiple functions: monitoring voltage and frequency, calculating phase differences, adjusting phase angles, and controlling the timing of reconnection. By consolidating these functions into a single intelligent controller, the system achieves fast synchronization without proportionally increasing overall system complexity.
Solution Approach 2:
The invention introduces an intelligent electronic device as an intermediary between the two power sources. This mediator monitors both sources, calculates the optimal reconnection timing, and actively adjusts parameters to achieve synchronization. The intermediary handles the complexity of phase shifting and voltage correction, allowing the rest of the system to remain relatively simple.
Data Source
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AI summary
A method for synchronizing and connecting a first sub power system with a second sub power system with an intelligent electronic device (IED) by use of at least one switching device between the first sub power system and the second sub power system in an electrical power system is provided. The method comprises the IED monitoring power supply parameters such as voltage magnitude, phase and other derived parameters such as voltage and phase differences in the first sub power system and the second sub power system to identify at least one instance for fast bus transfer where the two sub systems have acceptable differences in magnitude and phase. According to the identified one instance the IED has phase shifting or/and voltage magnitude correction carried out in anticipation for synchronizing power supplies on connection at the identified instance. The switching device is operated to make connection at the identified instance to have efficient and fast bus transfer. A synchronizing system is also provided.