Huaibei 750KV substation electrical installation project

Huaibei 750kV substation is the core project of the northern Anhui power grid upgrade, connecting the "Lianghuai" coal-fired power base with the Yangtze River Delta load center, and undertakes the dual tasks of regional energy transformation and new energy consumption. After the project is completed, it will optimize the main grid structure of Anhui power grid, improve the wind power and photovoltaic grid connection capacity in northern Anhui, and help the green and low-carbon transformation of old industrial bases.

Core content of electrical installation engineering

1. Main device integration and installation

• (1) 750kV main transformer:

• Single-phase autotransformer (3×500MVA), equipped with intelligent air cooling system and oil chromatography online monitoring (real-time analysis of H2, C2H2 and other gases), achieving fault warning accuracy of ±5%.

• Earthquake-resistant design: hydraulic shock-absorbing bearings are used to meet the 8-degree earthquake resistance requirements.

• (2) GIS combination appliances:

• 750kV fully enclosed gas insulated switchgear (GIS), integrated circuit breaker, disconnector and current transformer, partial discharge ≤3pC, suitable for the dusty industrial environment in Huaibei.

• Environmental optimization: using dry air (optimized N2/SF6 mixing ratio) instead of pure SF6, greenhouse gas emissions are reduced by 40%.

2. Intelligent and digital system

• (1) Digital Twin Operation and Maintenance:

• Build a three-dimensional visualization platform based on BIM+IoT to monitor equipment temperature rise, mechanical vibration and insulation status in real time, and support fault simulation and emergency plan drills.

• (2) Intelligent Inspection System:

• Equipped with a track-type inspection robot (equipped with an infrared thermal imager and an ultrasonic partial discharge detector), it covers the GIS room and the main transformer area, and the detection efficiency is increased by 60%.

3. Reactive power compensation and filtering system

• Static VAR generator (SVG): capacity ±300Mvar, dynamic response time ≤5ms, supporting the grid connection of new energy fluctuations.

• AC filter group: Equipped with 11/13th order double tuned filter, harmonic voltage distortion rate ≤1.0%, meeting the national standard (GB/T 14549).

4. Auxiliary system construction

• (1) Station power system: dual-circuit 10kV power supply, equipped with energy storage + rooftop photovoltaic (capacity 1.2MW) as emergency power supply, to ensure the black start capability of the entire station.

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• (2) Lightning Protection and Grounding:

• Composite grounding grid design (copper-clad steel + ion grounding electrode), grounding resistance ≤0.5Ω;

• Lightning intrusion wave protection for the entire station (MOA arrester with steep wave front protection).

Technical Difficulties and Innovation

1. Adaptability to complex environments

• Dust-proof design: The GIS room is equipped with a positive pressure dust-proof system (PM2.5 filtration efficiency ≥ 99%), and outdoor equipment uses anti-pollution flashover paint (RTV-II type).

• Anti-interference measures: The secondary cable shielding layer is double-ended and grounded, and the control room electromagnetic shielding level reaches Class A (≤1V/m).

2. High-precision installation process

• Main transformer in place: Hydraulic jacking and sliding technology is used to solve the problem of large equipment transportation in narrow and long station areas (error control ≤5mm).

• GIS docking: Laser tracker assists conductor plugging, contact resistance ≤10μΩ, annual leakage rate of air chamber<0.1%.

Implementation capabilities and advantages

1. UHV engineering experience

• The team participated in the Xinjiang Zhundong-Annan ±1100kV UHV project and the Qinghai-Henan 750kV interconnection project, and has the ability to build substations under complex working conditions.

2. Full-chain technical support

• (1) Design side: Jointly with North China Electric Power Design Institute to complete electromagnetic transient simulation (EMTP) and optimize overvoltage suppression scheme.

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• (2) Equipment side: The localization rate of core equipment exceeds 98% (XD Group main transformer, Pinggao Electric GIS).

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• (3) Construction end:

• Use 3D laser scanning technology to verify equipment installation accuracy (±1mm/m);

• Implement the requirements of the State Grid "Standard Process Library", and the first acceptance rate of key processes is 100%.

3. Green construction system

• During the construction period, prefabricated temporary buildings and low-noise machinery (≤65dB during the day) are used;

• The station area greening adopts local drought-resistant plants and is equipped with a rainwater recycling system (utilization rate ≥85%).

Project Value

• 1. Power transmission capacity: The long-term planned capacity is 1500MVA, with an annual power transmission of more than 30 billion kWh, which can replace 9 million tons of standard coal and reduce carbon dioxide emissions by 24 million tons/year.

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• 2. Social benefits:

• Ensure the clean transformation of the Huaibei coal-fired power base and support the electricity demand of the ceramic aluminum new materials and high-end equipment manufacturing industrial park;

• Enhance the carrying capacity of Anhui power grid for distributed photovoltaic and energy storage power stations, and help build a "dual carbon" demonstration zone.