Load Phase-Back Control for Hybrid Fracturing Power Disturbances
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Solution Overview
Problem
Existing well stimulation operations, such as hydraulic fracturing, face challenges with power supply limitations and disruptions, leading to potential blackouts and operational downtime due to fluctuations in input voltage and frequency, especially when using variable frequency drives (VFDs) for pumping units.
Innovation Solution
The implementation of a blender power unit (BPU) and a load phase back system that manages power distribution by reducing loads during voltage and frequency disturbances, allowing for hybrid operation with diesel systems and independent electrical supplies, and using motor soft starters to minimize capital costs and extend equipment life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If variable frequency drives (VFDs) are used for pumping units, then operational flexibility and control are improved, but power supply limitations and disruptions cause blackouts and operational downtime
Solution Approach 1:
The system dynamically adjusts operational parameters by transitioning between grid power and diesel generator power based on detected power quality conditions. When voltage or frequency deviations exceed thresholds, the system automatically switches power sources and implements load phase-back, changing the operational state to maintain reliability while preserving VFD flexibility.
Solution Approach 2:
The power management system continuously monitors voltage and frequency parameters from the grid supply and uses this feedback to automatically control the diesel generator and VFD operations. The system adjusts generator output and load distribution based on real-time power quality measurements, enabling automatic response to disruptions without operator intervention.
2Reliability
If hybrid operation with diesel systems is implemented, then power supply reliability is improved, but system complexity increases
Solution Approach 1:
The system merges grid power and diesel generator power into a unified power distribution network. The power management controller integrates both sources, automatically selecting and coordinating them to supply the fracturing pumps and auxiliary loads, thereby achieving reliable hybrid operation while managing complexity through centralized control.
Solution Approach 2:
The diesel generator serves multiple functions: it can operate in parallel with the grid to supplement power during high-demand fracturing operations, and it can independently supply full load when grid power is unavailable or unstable. This multi-functionality maximizes the utility of the diesel system while maintaining reliability across varying operational conditions.
3Productivity
If load phase back system is used, then recovery from power disturbances is accelerated, but control system complexity increases
Solution Approach 1:
The load phase-back system pre-establishes prioritized load groups before power disturbances occur. When voltage or frequency deviations are detected, the system automatically implements pre-planned load reduction sequences, shedding non-critical loads first to rapidly stabilize power consumption and accelerate recovery without requiring complex real-time decision-making during disturbances.
4Duration of action of stationary object
If motor soft starters are used, then equipment life is extended and capital costs are reduced, but starting torque control capability is limited
Solution Approach 1:
The system uses the diesel generator as an intermediary power source during motor starting operations. The generator provides controlled power during startup, enabling soft starting of large motors without requiring expensive VFDs or complex starting circuits. This approach extends equipment life by reducing mechanical stress while maintaining adequate starting torque through generator control.
Data Source
AI summary
A load phase back system for controlling a plurality of electrical loads in an electric fracturing spread. The load phase back system comprises monitoring circuitry configured to monitor input power received from an electric power source. The monitoring circuitry determines a measured voltage and a measured frequency of the input power. A controller controls the power applied to the plurality of electrical loads from a power bus according to a value of the measured voltage and a value of the measured frequency of the input power. The controller reduces power applied to selected ones of the plurality of electrical loads from the power bus when at least one of the measured voltage is less than a first threshold and the measured frequency is less than a second threshold.