Autotransformer Reactive Power Compensator Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing reactive power compensators face challenges with surge voltage handling, high voltage differences between autotransformer windings, and complex structures, leading to increased insulation requirements and housing size, as well as difficulties in managing short circuits and adjusting reactive power effectively.
Innovation Solution
A reactive power compensator design featuring an autotransformer with primary windings connected to live line leads and secondary windings star-connected to form a star-point, allowing for adjustable reactive power compensation using both reactor and capacitor banks with an on-load tap-changer and external components, enabling easier surge voltage handling and reduced insulation needs, along with a three-phase on-load tap-changer and circuit breakers for automatic compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the secondary winding of the autotransformer is connected to the live first end of its primary winding, then adjustable reactive power compensation can be achieved, but the insulation requirements and housing size increase due to high surge voltages
Solution Approach 1:
The patent divides the autotransformer into separate primary and secondary windings with distinct connection points. The secondary winding is connected to the second end of the primary winding rather than the live first end, segmenting the high voltage path and reducing surge voltage exposure for the reactive bank, thereby lowering insulation requirements while maintaining compensation functionality.
Solution Approach 2:
The patent introduces an intermediary connection structure where the secondary winding connects to the second end of the primary winding through a controlled path. This intermediary connection acts as a mediator that limits voltage surge propagation to the reactive bank, reducing the insulation burden while preserving the autotransformer's voltage adjustment capability for reactive power compensation.
2Adaptability or versatility
If the secondary winding is connected to the live first end of the primary winding, then voltage adjustment is possible, but the housing size increases due to required clearance from live parts to earthed parts
Solution Approach 1:
The patent segments the autotransformer winding connections to separate the high voltage live first end from the secondary winding connection point. By connecting the secondary winding to the second end of the primary winding instead, the high voltage clearance requirements are localized, allowing for a more compact housing design while maintaining full voltage adjustment capability.
3Adaptability or versatility
If a plus/minus switching is used for the tap changer, then the number of adjustment steps is doubled, but the voltage of the reactor or capacitor live first end reaches higher levels than the nominal phase voltage
Solution Approach 1:
The patent inverts the conventional tap changer connection approach. Instead of connecting the tap changer to the live first end of the primary winding, it connects to the second end, which is at a lower potential during normal operation. This inversion allows the plus/minus switching to provide doubled adjustment steps without exposing the reactor or capacitor to excessive voltage levels beyond the nominal phase voltage.
4Adaptability or versatility
If the secondary winding is connected to the live first end of the primary winding, then reactive power compensation can be achieved, but three separate one-phase tap changers are required for a three-phase system
Solution Approach 1:
The patent merges the three-phase tap changer requirements into a single combined unit. By connecting the secondary winding to the second end of the primary winding, the patent enables the use of one integrated three-phase on-load tap changer instead of three separate one-phase tap changers, reducing device complexity while maintaining reactive power compensation capability across all three phases.
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
This design simplifies autotransformer dimensioning, reduces insulation material and housing size, allows for cost-effective three-phase on-load tap-changers, and enhances the ability to withstand short circuits, while enabling automatic compensation of both capacitive and inductive reactive power with a single arrangement.
Implementation Method 1
an autotransformer with primary windings connected to live line leads and secondary windings star-connected to form a star-point
Implementation Method 2
reactor or capacitor bank can be measured to create reactive power
Implementation Method 3
capacitor bank could comprise several capacitors equipped with a circuit breaker
Data Source
Figure 1
Figure 2
AI summary
A reactive power compensator for an electric power transmission or distribution network comprising reactive components (9) for compensating reactive power and an autotransformer (6) with pairs of primary windings (5) and secondary windings (7), the primary windings for connecting the autotransformer (6) to power lines (3) and the secondary windings (7) for connecting the autotransformer (6) to second poles (9b) of the reactive components (9), the primary windings (5) being star-connected to form a star-point (8) and the secondary windings (7) being connected to the star-point (8) of the autotransformer (6).