Knowt
1740978737756_Jurnal_Transmisi_Bawah_Tanah
Abstract
Cable Types and Risks: Cable lines in gas processing areas pose unique risks due to explosion potential from gas. Proper planning for underground cables is essential to mitigate these risks.
Cable Specifications: For underground installations, cable type and size must consider area classification, installation method, load data, cable data, and safety measures.
Temperature Considerations: Evaluations for short circuit temperature rises, derating factors, and voltage drops are necessary.
Selected Cable: N2XSEBY cable with copper conductors and XLPE insulation is chosen for installation due to its mechanical protection in case of fire.
Cable Sizes: Required sizes are 35 mm² for 20 kV medium voltage and 120 mm² for 6.6 kV.
1. Introduction
Energy Distribution Systems: Industrial electrical distribution can be through overhead systems or underground cables. Choosing the right system impacts reliability and maintenance costs.
Usage in Gas Processing Plants: Underground cable installations, like that in PT. Medco E&P Melaka's Block A gas processing project, utilize XLPE insulated cables due to safety and reliability.
2. Cable Selection and Methodology
2.1 XLPE Cables Overview
Material Properties: XLPE is favored for insulation due to high dielectric strength and mechanical durability, even at elevated temperatures.
Heat Considerations: Cable heat dissipation in underground installations is crucial, as thermal resistance from surrounding soil increases operational risks.
2.2 Research Methodology
Literature Review: Initial theory and concepts were gathered from relevant books and journals.
Field Study: Direct observations on-site were conducted to gather accurate data, particularly for Block A Aceh project.
3. Research Methodology for Cable Size Calculation
3.1 Steps for Cable Selection
a. Area Classification and Installation Method
Study the nature of hazards and define zones to determine suitable installation methods.
b. Load Data and Protection Mechanisms
Consider load capacities, cable protection, and environmental factors influencing installation.
c. Temperature Rise from Short Circuits
Calculate cable sizing based on potential temperature increases during faults.
d. Derating Factors
Assess operational derating to ensure cables meet safety requirements.
e. Voltage Drop Evaluation
Check voltage drop across cable length to ensure it meets operational standards.
4. Cable Construction
4.1 Main and Auxiliary Components
a. Conductor
Conductors are made of copper or aluminum. Copper’s superior electrical and mechanical properties make it preferable in gas industries.
b. Insulation
Insulating materials must offer high dielectric strength, be temperature resilient, and have low moisture absorption.
c. Mechanical Protection
Cables must be protected from environmental damage, including mechanical impacts and corrosion.
4.2 Types of XLPE Cables
Cable Types: N2XSEY cables are discussed for their protective features and economic viability.
5. Installation Method for Underground Cables
5.1 Direct Burial Standard
Cables are buried directly in the earth, approximately one meter deep, to minimize the risk of fire propagation. This method provides good mechanical protection and is cost-efficient.
Installation Process: Include clean sand bedding, protective concrete tiles, warning tape, and proper spacing between cables for minimized risk of damage.
6. Results and Discussion
6.1 20 kV Cable Calculations
a. Load Calculations
Calculated full load arcing at 18.19 A and proposed cable size of 35 mm², based on thermal and voltage drop criteria.
b. Short Circuit Specifications
Minimum area based on short circuit calculations found to be 1.998 mm²; selected cable appropriately exceeds this figure.
6.2 6.6 kV Cable Calculations
a. Load Calculations for Compressor Motor
Full load calculated at 39.59 A, with proposed cable size of 120 mm² to meet operational standards for both steady-state and starting conditions.
7. Conclusions
Safety Considerations: In gas processing areas, direct burial of cables provides adequate mechanical protection and minimizes fire spread risks.
Recommended Cable Sizes: 35 mm² for 20 kV and 120 mm² for 6.6 kV installations to ensure optimal performance and safety.
References
Alan L. Sheldrake (2003). Handbook of Electrical Engineering For Practitioners in the Oil, Gas and Petrochemical Industry.
IEC 60079-14 (2013). Electrical installation design, selection and erection standard.
Additional industry references to support technical specifications and installation standards.
