Life cycle cost analysis of medium and high voltage circuit breakers

2025-07-29 13:50:21

In power equipment management, the life cycle cost (LCC) analysis of medium and high voltage Circuit breakers is a core tool for optimizing investment decisions. It not only focuses on procurement prices, but also covers all costs of equipment from "birth" to "retirement", with the ultimate goal of achieving the unity of minimizing total costs and maximizing reliability. The following provides a systematic analysis of how to achieve optimal cost-effectiveness, including cost composition, optimization strategies, practical cases, and implementation paths.

 1、 Composition and Key Influencing Factors of Life Cycle Cost (LCC)

The medium and high voltage circuit breaker LCC includes the following core modules, each of which needs to be considered:

1. Initial investment cost (Ci)

-Equipment purchase cost (such as minrongZW8-12 about 5000 to 8000 yuan, VD4G-50 about 200000 to 500000 yuan)

-Installation and debugging fees (approximately 10% -15% of the purchase cost)

-Cost of supporting monitoring system (such as installing intelligent sensors and relay protection units)

2. Operation and maintenance costs (Co)

-Periodic maintenance: annual inspection, preventive testing (approximately 2% of equipment price per year)

-Daily inspection: labor and testing equipment costs

-Energy consumption cost: power consumption for circuit breaker operation and auxiliary systems

3. Fault cost (Cf)

-Repair costs: replacement of spare parts, manual repair (single failure costs can reach tens of thousands of yuan)

-Liuzhou Power Supply Bureau once suffered annual losses exceeding one million yuan due to circuit breaker misoperation or refusal to operate

4. Retirement disposal cost (Cd)

-Demolition, transportation, and environmental treatment fees

-Equipment residual value recovery (approximately 5% of purchase cost)

5. Hidden costs

-Technological obsolescence leads to early replacement (such as a sharp decline in the efficiency of equipment that is over 15 years old)

-Chain risk caused by decreased system reliability

2、 Cost effectiveness optimization strategy: from selection, operation and maintenance to update decision-making

To achieve LCC minimization, it is necessary to run through all stages of the equipment lifecycle:

1. Scientific selection: matching scene requirements

-Economic scenario (such as rural power grid renovation): Choose minrongZW8-12 type (domestically produced, cost-effective, and with a mechanical lifespan of ≥ 20000 times)

-High reliability scenario (such as power plant export): Choose ABB VD4G-50 (50kA disconnection, maintenance free design, LCC cycle savings of $100000)

-Heavy pollution/coastal environment: choose silicone rubber material for external insulation (salt spray resistance, hydrophobic migration level HC3)

2. Optimization of operation and maintenance strategy: Predictive maintenance replaces regular maintenance

-Predicting failure rates based on principal component analysis (PCA) to reduce unnecessary downtime

-Deploy intelligent monitoring (such as VD4-CS built-in "health prediction system")

-Combining vibration signal analysis and temperature monitoring to achieve precise maintenance

3. Key technologies for cost control

-Retirement factor for service life: Correction of equipment failure rate function after maintenance to extend effective lifespan

-Factory maintenance:A Power Supply Bureau adopts this mode to save 69.91 million yuan in costs

-Domestic substitution: For example, the CM series circuit breaker has a 30% lower price than foreign counterparts while maintaining the same performance

3、 Practical cases and technical support

1. Reference for successful cases

-Liuzhou Power Supply Bureau: Through LCC model optimization of maintenance strategy (2013-2016), implemented 137 projects with a total investment of 36.61 million yuan, saved 69.91 million yuan, and extended the service life of key equipment by 30%.   

-Changshu Switch: Provides a "same price upgrade solution" for old circuit breakers, combined with digital monitoring (CS Smartlink system), reducing operation and maintenance costs by 40%.

2. Digitization and modeling tools

-Principal Component Analysis (PCA): Processing missing data, extracting the main causes of faults (such as mechanical wear and insulation degradation), and improving the accuracy of LCC calculations.   

-System Dynamics Model: Dynamically simulate cost fluctuations (such as failure rate λ changing with maintenance frequency) and optimize maintenance cycles.

4、 Implementation Path: Four Steps to Achieve LCC Optimization

1. Data collection stage

-Establish equipment files: model, commissioning time, historical fault records, maintenance costs.   

-Install sensors to monitor current, temperature, and mechanical vibration status.

2. Modeling and simulation

-Construct an LCC model using PCA or system dynamics, with input parameters including:

-Discount rate (recommended at 5% -8%)

-Failure rate curve (manufacturer data+operational correction)

-Electricity price and unit price for power outage losses

3. Strategy formulation and execution

-Economic life assessment → development of update plan (e.g. minimum annual LCC in the 20th year)

-Choose maintenance mode: preventive, predictive, factory based maintenance

4. Continuous optimization

-Update LCC model parameters annually

-Combining new technology iteration strategies

summarize

Maximizing the cost-effectiveness of medium and high voltage circuit breakers is essentially the result of refined cost management throughout the entire cycle and precise matching of reliability requirements

-Selection stage: Reject the "low price theory" and attach importance to scene adaptability (such as selecting silicone rubber insulation for heavily polluted areas);   

- Operation and maintenance phase: shifting from "regular maintenance" to "status maintenance", using tools such as PCA to reduce sudden failure losses;   

- Update decision: Take the economic lifespan as the node, and proactively replace old equipment with new ones (priority evaluation>15 years);   

-Localization and digitalization: Domestic high-end alternatives and intelligent monitoring systems have become powerful tools for cost reduction and efficiency improvement.   

The ultimate goal is not only cost compression, but also to achieve dual improvement of asset health and power supply reliability through scientific allocation of cost structure. Electric power companies can refer to the steps in the article to establish an LCC management system and gradually shift towards lean asset management.