Series-Capacitor TCBR Circuit for Grid Fault Voltage Stability
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Solution Overview
Problem
Power grids are vulnerable to generator tripping due to reactive power consumption by thyristor controlled braking resistors (TCBRs) during faults, leading to undervoltage and potential shutdowns.
Innovation Solution
A system comprising a thyristor controlled braking resistor (TCBR) with a series-connected capacitor to absorb reactive power, maintaining grid stability by compensating for reactive power consumption, and optionally including a transformer and bypass switch for enhanced control and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thyristor controlled braking resistor (TCBR) is used to absorb power from the generator during a fault, then the generator can avoid tripping and provide continued power, but the TCBR consumes reactive power which decreases grid voltage and may force the generator to trip on undervoltage
Solution Approach 1:
A capacitor is introduced as an intermediary component connected in series with the TCBR. This capacitor compensates for the reactive power consumed by the TCBR's internal inductance and thyristors, thereby maintaining voltage levels and preventing generator tripping on undervoltage while preserving the TCBR's ability to absorb active power during faults
2Reliability
If shunt capacitor banks are used to compensate for reactive power absorption by the TCBR, then the risk of generator tripping is mitigated, but the system complexity increases with mechanically or thyristor switched capacitor banks
Solution Approach 1:
The compensation function is extracted from a complex switched capacitor bank system and implemented through a simple series capacitor connected directly with the TCBR. This eliminates the need for mechanical or thyristor switching mechanisms while providing continuous reactive power compensation proportional to the TCBR current
Solution Approach 2:
The series capacitor automatically provides reactive power compensation that is proportional to the current flowing through the TCBR. The compensation level self-adjusts based on the fault conditions and TCBR operation, eliminating the need for external control systems or switching mechanisms
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system stabilizes power grids by preventing generator tripping and maintaining voltage stability through dynamic reactive power compensation, enhancing resilience and reliability.
Implementation Method 1
provide a capacitor electrically connected in series with the TCBR, wherein the capacitor is configured to compensate for the at least a portion of the reactive power component absorbed by the TCBR
Implementation Method 2
a thyristor electrically connected in series with the resistor, configured to control the electrical load drawn by the braking resistor
Implementation Method 3
a braking resistor configured to draw an electrical load from the generator during a fault on the power line
Data Source
AI summary
A system (100) for stabilising a power grid (102), comprising a generator (104), configured to provide power to the power grid (102), the power having an active power component and a reactive power component, and a power line (106), configured to transmit power from the generator (104) to the power grid (102). The system (100) comprises a thyristor controlled braking resistor (TCBR) (108) arranged on the power line (106), and a capacitor (110) electrically connected in series with the TCBR (108). The TCBR (108) absorbs at least a portion of the reactive power component from the generator (104) during a fault on the power line (106) and the capacitor (110) is configured to compensate for the at least a portion of the reactive power component absorbed by the TCBR (108).