[VIDEO] Quang Anh – Contractor for Turnkey Execution of 250kVA Transformer Substation

Quang Anh Electrical Construction Company Limited was established in Vietnam. We are a contractor specializing in consulting, designing, and executing turnkey projects for medium and low voltage power lines up to 35kV and 250kVA transformer substations with high progress, quality, and technical requirements.

Quang Anh Electrical Construction Company is growing rapidly with experienced leaders and young, enthusiastic, and dynamic staff. Our team has taken on many important positions in large electricity companies and corporations, participating in the design and construction of numerous 22kV, 35kV power lines, 250kVA transformer substations, and various types of industrial electrical cabinets that have achieved high efficiency. We are confident that we will be a reliable and high-quality choice for your turnkey construction project of a 250kVA transformer substation.

Regarding pricing and equipment materials:

 

Quang Anh always provides genuine materials and equipment with full CO and CQ certificates. We carry out the construction of 22kV power lines and 250kVA substations with a high sense of responsibility, ensuring on-time delivery and quality for investors.

Our technical and construction methods are constantly innovated to suit each project’s characteristics. We always enthusiastically support our customers with any difficulties and questions. The price of the complete construction of a 250kVA substation is always competitive, bringing the highest economic efficiency to the investor.

All of these quality policies are determined to be implemented by our entire leadership and staff.

The actual price of the complete construction of a 250kVA substation depends on each location or different industrial zones. It depends on the location, connection method, distance from the connection point to the substation, and equipment according to the substation.

The 250kVA transformer machines include THIBIDI, MIEN NAM, EMC, SANAKY, SHIHLIN, AGE, HEM, EEMC.

Switching equipment includes Mitsubishi, LS.

Electrical cables include Thinh Phat, Cadivi, LS.

Insulators, LA, FCO, LBFCO, and other auxiliary equipment are also included.

I- Main materials and equipment for the complete construction of a 250kVA substation:

1. Power line and medium voltage equipment.

a- Concrete pole 12m, 14m, pole foundation

The BTLT electrical pole with a prestressed force of 12m -7.2 kN, 190mm, 350mm, 7.2KN.

• Due to pre-stressed concrete, the product of prestressed centrifugal concrete electrical pole will not be deformed, cracked during transportation, construction, and use.
• Pre-stressed concrete combined with centrifugal rotation has made the concrete pole solid, durable, able to withstand high loads, not cracking, increasing the ability to resist water penetration, corrosion of steel reinforcement, and sulfate corrosion.
• The use of high-strength concrete and steel reduces the cross-sectional area of the steel reinforcement, leading to a significant reduction in product weight, facilitating relocation, transportation, construction, and installation.

b- L75x75x8 steel beam, 2.4m long + 2 pieces of 60x6x920 bracing bars – 04

• The steel components are hot-dip galvanized.
• There are 2 types of covering: 100mm or 80mm.
• Thickness: 8mm or 6mm.

c- LBFCO 200A-24kV polymer fuse switch – 03

• Rated voltage: 24kV
• Rated current: 100A-200A
• The fuse switch cuts off the arc generated during the switching operation.
• The body is made of lightweight polymer material, easy to store, transport, and install.
• High length of fuse tube: >590mm
• AC voltage withstand test: Dry 75kV, Wet 50kV
• Impulse voltage withstand test: 125kV (1.2/50 micro sec)
• High mechanical strength.
• Suitable for harsh operating environments such as high pollution, acid, and sea salt.
• Standard: IEC 60282-2:1995

d- LB FCO cover – 03

Technical characteristics of the non-flame retardant type:

• Hardness (Shore A): 50-65
• Breakdown voltage: ≥ 50kV
• Operating voltage: up to 36 kV
• Short-term temperature resistance (10s): ≥ 260°C
• Continuous temperature resistance (10min.): ≥ 180°C

e- 24kV Polymer DR600 Insulator + Unshielded Suspension Clamp – 06

• Rated voltage: 15 kV
• Creepage distance: 600 mm
• Bending load: 13 kN
• Dry power frequency withstand voltage (1 min): 75 kV
• Wet power frequency withstand voltage (1 min): 55 kV
• Lightning impulse withstand voltage: 125 kV
• Dry flashover distance: 240 mm

 

f-Composite beam 2.4m with LBFCO installation

• Good insulation and thermal insulation properties.
• Made of high-quality fiberglass, with good impact resistance.
• Resistant to corrosion and rust – especially suitable for use in harsh weather conditions including coastal areas with high humidity, deserts with acid and alkali conditions.
• Lightweight, about 1/3 the weight of steel materials. Easy to install and transport, saving labor costs, time and equipment.
• Low maintenance costs.

e- Composite Line Tie 50-06

The composite line tie is used to tie the conductor on the insulator for both suspension and dead-end insulators, applicable for line angles up to 15°.

Tests have shown that the composite line tie and insulator cap will develop load sharing and keep the conductor equivalent to or superior to hand-tied conductors.

Load-holding capacity is the ability of the tie to maintain holding and uniformity on conductors and insulators when subjected to continuous and uneven stress due to wind-induced motion, branch impacts, and an imbalance in the range of sag. This imbalance is usually low when caused by wind motion and tree branch impacts, and serious when the conductor is broken.

g- Hotline clamp 2/0 – 03

The Hotline clamp 2/0 – 03 is a specialized accessory for cables from 35-70mm2. The clamp is used to split the cable connection from aluminum to copper down to the transformer station or metering point on the power line. The clamp body is made of aluminum alloy and the clamp is made of pre-cast copper.

Materials and technology: The body is made of aluminum, the U-shaped bolt is made of high-quality copper. The integral casting technology focuses on the junction between the copper clamp and the aluminum body to ensure electrical conductivity. The bolt head is hot-dip galvanized with a thickness of 0.08mm. The surface is clean, free of cracks, burns, rust, and other details are cleaned with a brush.

h- Hotline clamp cover – 03

The Hotline clamp cover is used to insulate the clamp terminal. It is designed to prevent incidents caused by animals and trees, ensuring continuous power grid operation and reducing damage caused by electrical incidents.

Technical specifications for non-flame-retardant type:

• Hardness (Shore A): 50-65
• Breakdown voltage: ≥ 50kV
• Operating voltage: up to 36 kV
• Short-term withstand temperature (10s): ≥ 260OC
• Continuous withstand temperature (10min.): ≥ 180OC

i- CXV/DSTA/PVC 3×50 Medium voltage submarine cable 12/20/24KV

Medium voltage CXV/SE/DSTA 3×50 Cadivi cable is used for transmission and distribution of medium voltage electricity with 3 cores and a nominal cross-sectional area of 50mm2 to ensure efficient electricity transmission.

Conductor: Copper

Conductor shield (inner semiconducting layer): covered with semiconducting material

Insulation: XLPE

Outer semiconducting layer: covered with semiconducting material

Metal shield: copper tape is directly wrapped around the outer semiconducting layer of each cable core

Bedding layer: made of PP or PVC material

PET tape (if any): wrapped around the core bundle in case the bedding layer is PP

Separation layer (if any): PVC plastic

Protective steel tape armor: 2 layers of zinc-coated steel tape

Outer sheath: PVC

APPLICABLE STANDARD: 

TCVN 5935-1995/IEC 502 Medium Voltage Aerial Cable rated at 24kV

IEC 60502 Waterproofing compound for the conductor

TECHNICAL SPECIFICATIONS

Voltage rating U0/U: 12/20(24)kV

Conductor cross-section: 50mm2

Construction: 19/1.83No/mm

Conductor diameter: 8.37mm

Maximum DC resistance at 20°C: 0.387Ω/km

Insulation thickness: 5.5mm

Jacket thickness: 2.9mm

Overall diameter: PP: 62.3mm, PVC: 63.5mm

Cable weight: PP: 5392kg/km, PVC: 6610kg/km

Cable length: 0.5km

k- 24kV 50mm² Copper Tape Screened Medium Voltage Cable

The conductor material is solid copper wire.

The conductor is constructed with concentrically twisted copper wires that are not tightly compressed.

It has WBC conductor waterproofing.

The conductor shield is a layer made of semiconductor material.

It has XLPE insulation.

The outer jacket is made of PVC.

L – Submarine medium voltage cable end 3x50mm2 24kV OD, heat shrinkable joint + coss.

The submarine cable head is designed for voltage levels from 24kV to 36kV with outstanding features:

• Easy to install
• Quick operation
• Long service life
• Resistant to harsh weather and UV rays
• Flexible with the shape and material of the conductor

Technical specifications:

Description of the heat shrink cable joint box

All heat shrink cable joint boxes have adhesive lining inside the tube to prevent rainwater from penetrating and increase the adhesion of the cable head. For single-core cables, only one heat shrink tube is needed. The phases of the cable head are marked with colors in order, making it convenient to install the cable head without confusion. All materials that make up the cable head are capable of withstanding UV rays and various weather conditions.

Product features of the heat shrink cable joint box:

• Easy and quick installation
• Scratch and wear-resistant
• Versatile and widely applicable for cables
• Environmentally friendly and protective
• m- Submarine cable head support 3×50 (V50)

The underwater cable head support is made of V50, V63 or V75 steel, double welded and hot-dip galvanized. It is used to support the medium voltage underwater cable head.

n- HDPE pipe 130/100

Outer diameter: 130 ± 4.0 mm. Inner diameter: 100 ± 4.0 mm. Thread pitch: 30 ± 1.0 mm. Minimum bending radius: 400 mm. Common length of pipe coil: 100 m.

2. FCO dropout fuse and connection

a- FCO 27KV 100A 12KA DR550 polymer – 03

This is a polymer-made FCO (fuse cutout) with the following specifications:

• Rated voltage: 27KV
• Rated current: 100A – 200A
• Lightweight and easy to store, transport, and install
• High mechanical strength
• Suitable for harsh operating environments, including high pollution, acid, and saltwater environments
• Rated industrial frequency withstand voltage: Dry 75KV, Wet 50KV
• Rated impulse withstand voltage: 125KV (1.2/50micro sec)
• Conforms to IEC 60282-2: 1995 standard
• High voltage standoff distance: >590mm

b- High voltage fuse wire 50K – 03

This wire is made of lead material with a melting temperature of 327ºC. It is used as a fuse wire in high voltage fuses to protect devices and high voltage lines from overcurrent.

c- Composite beam 75x75x6x3000mm – 01

This is an insulation material made of high-quality glass fiber, with the following features:

• Good insulation and thermal insulation properties
• Resistant to impact and corrosion, especially suitable for use in harsh weather conditions, including coastal areas with high humidity and deserts with acid and alkali conditions
• Lightweight, about one-third the weight of steel, making it easy to install and transport, thus saving labor costs, time, and equipment
• Low storage cost.

a- LA 18KV 10KA – 03 (LA – LIGHTNING ARRESTER or SURGE ARRESTER)

Applicable standard: IEC 60099-4

Rated voltage: 18kV (other voltage ranges include: 3-6-9-12-15-18-21-24-27-30-33-36kV)

Rated surge current: 10kA

Rated frequency: 50Hz

Insulation material: Polymer (Silicone Rubber)

Structure:

• It is a gapless lightning arrester used for power distribution grids.
• The basic structure of the lightning arrester consists of stacked metal oxide varistor (MOV) discs connected to two electrodes, tightly wrapped with layers of epoxy-impregnated glass fibers to form a durable block with high electrical and mechanical bending strength.
• The Polymer (Silicone rubber) insulation material has high durability, particularly suitable for operation in polluted environmental conditions such as coastal areas, salt fog, industrial pollution, UV radiation, and tropical climates.

b- CXV-25-24kV medium voltage cable

CXV-25 is a type of hanging medium voltage cable used for transmitting and distributing power in the air, providing a voltage of 12/20 (24) kV or 12.7/22 (24) kV, a frequency of 50Hz, and installed on poles.

• Hanging medium voltage cable 12/20 (24) kV or 12.7/22 (24) kV, copper core, XLPE insulation, PVC sheath.
• Hanging medium voltage cable used for transmitting and distributing power, providing a voltage of 12/20 (24) kV or 12.7/22 (24) kV, a frequency of 50Hz, and installed on poles.
• The long-term allowable working temperature for CXV-25 – 12/20 (24) kV cable is 90ºC.
• The maximum allowable temperature during short circuit is 250°C for no more than 5 seconds.
• Applicable standard: TCVN 5935-1

Cable structure

• Cross-sectional area: 25mm².
• Conductor: Concentric twisted copper core, not tightly pressed, twisted from rigid copper wires without waterproofing.
• Insulation layer: XLPE.
• Outer sheath: PVC.

c- 8mm BassLI LA-tole bracket

d- Insulation cover for LA electrode protection

The LA insulation cover is made of silicone rubber material with chemical reinforcement against UV radiation, good insulation ability, operating voltage up to 36kV, breakdown voltage ≥50kV, continuous heat resistance up to 180°C, water-resistant, dust-resistant, and less prone to aging.

4- 250KVA transformer mounting bracket

a- Transformer platform beam 250KVA U200x74x3000mm (2800mm hole spacing)

The MBA platform beam U200-3m (transformer platform beam for 250KVA transformer station) is made of U200 steel with hot-dip galvanized surface. The U200-3m steel beam is used to support the transformer at the 250KVA substation.

b- Iron cover beam (U120x52x790mm)

The U120-0.79m cover beam is made of U120 steel with hot-dip galvanized surface.

c- Transformer fixed beam 250KVA (U120x52x1000mm)

The U120 fixed beam is made of U120 steel with hot-dip galvanized surface. The U120-1m steel beam is used to fix the 250KVA transformer.

5- Equipment installation beam (for installing jumpers and MCCB cabinets)

a- L75x75x8x3000mm steel angle bar (with 3 brackets and a 2800mm hole center)

• The 3-meter long steel angle bar is made from 3-meter steel bars with an L-shaped cross-sectional profile. The steel is produced on a modern production line according to ASTM, JIS G3101, KD S3503, GB/T 700, EN10025-2, A131 standards.
• Steel parts are hot-dip galvanized.
• Bracket type: 3 brackets with a pre-drilled 80mm diameter hole at the 2.8m center.
• Thickness: 8mm

b- L75x75x8x3000mm steel angle bar (without brackets and with a 2800mm hole center)

• The 3-meter long steel angle bar is made from 3-meter steel bars with an L-shaped cross-sectional profile. The steel is produced on a modern production line according to ASTM, JIS G3101, KD S3503, GB/T 700, EN10025-2, A131 standards.
• Steel parts are hot-dip galvanized.
• Bracket type: 0 bracket, with a pre-drilled 80mm diameter hole at the 2.8m center.
• Thickness: 8mm

6- Standing insulation.

DR600-06 24kV Standoff Insulator

• Rated Voltage: 15 kV
• Length of insulator: 600 mm
• Bending Load: 13 kN
• Dry Power Frequency Withstand Voltage (1 minute): 75 kV
• Wet Power Frequency Withstand Voltage (1 minute): 55 kV
• Impulse Withstand Voltage: 125 kV
• Dry Flashover Distance: 240 mm

7- 250KVA 22/0.4kV Transformer

a. Main technical specifications:

No-load loss Po (W): 700 No-load current Io (%): 2 Short-circuit loss at 75 degrees C Pk(W): 3250 Short-circuit voltage Uk (%): 4

b. Size of 250KVA transformer

L: 1030 W: 914 H: 1470 A: 550 c. Weight of 250KVA transformer Oil: 273 Core: 663 Total: 1200

8 – Low voltage side of 250KVA transformer

a- CV/600V-240mm2 cable for 250KVA transformer output

CV power cable with stranded conductor and PVC insulation, used for power transmission and distribution systems, rated voltage 0.6/1 kV, for fixed installation.

Applicable standards:

AS/NZS 5000.1 AS/NZS 1125

Identification:

• By color of insulation: Black
• Or by customer’s requirement Voltage rating U0/U: 0.6/1 kV Test voltage: 3.5 kV (5 minutes) Long-term allowable working temperature of conductor: 70°C Maximum allowable temperature of conductor during short-circuit within no more than 5 seconds is: 140°C for cross-sections greater than 300mm² 160°C for cross-sections less than or equal to 300mm²

9 – MCCB panel 400A & 125Kvar capacitor bank

The cabinet shell is 2mm thick with two compartments (one for a 400A MCCB and one for a 125Kvar capacitor bank) with a 50cm high canopy and suspension pole.

The cabinet frame meets the standards of IP43-IP55 and is made of 2mm electrostatically coated steel plates. The standard followed is IEC 60439-1 with a rated current of 0.4kA – 50Hz and a minimum/maximum current used of 100A – 6300A.

a) 400A 3P MCCB

The MCCB is a 3P 400A 45KA automatic block type switch with product code ABN803c. It has a short-circuit breaking capacity of 45kA and a rated voltage of 220-240V. Its Icu is capable of withstanding the fault current for one second. Its rated voltage of 400V/440V is widely used in civil and large projects. MCCB LS is manufactured using advanced and modern technology, ensuring good quality and safety for users.

Regarding its operating principle, when installing the 400A MCCB, a safe distance is always maintained between the device and the board, bar, and other protective devices. When a short circuit occurs, the high temperature and pressure in the electric arc chamber are cut off to prevent current-induced fire.

Other components include: Volt meter + SW, Ammeter + SW, fuse + base, Phase indicator light (red + yellow + green), 400/5A measuring current transformer.

b) 125Kvar CSPK 3P capacitor bank (1 base level of 25kVAR + 4 control levels of 25Kvar)

The CSPK 125Kvar capacitor bank is usually installed in the MCCB 400A cabinet at a 250KVA transformer substation. It is used to compensate for reactive power to raise the power factor cosφ > 0.9 (cos phi) to ensure the efficiency of the power grid and avoid reactive power penalty as per the regulations of the power industry.

Therefore, installing a capacitor bank can significantly reduce monthly electricity bills (up to several tens of percent). The 3P 440V 25Kvar (dry) capacitor is the main component in the 125Kvar reactive power compensation cabinet, along with other devices to ensure the intelligent, stable, and safe operation of the compensation system, such as:

MCCB 3P 250A 45Ka – 01, Contactor 3P 32 – 07, 3P 440V 25Kvar (dry) capacitor – 05, Capacitor control unit – 01, Volt + Ammeter, 400/5A measuring current transformer – 01, fuse + base – 04, Phase indicator light (red + yellow + green) – 03, 400A 8 x 30 + thermal strip.

10 – 250KVA transformer substation ground.

The grounding system in a substation, also known as the grounding system, plays an important role in operation.

When an insulation failure occurs in an electrical device, a short-circuit current or leakage current will flow through the device casing or along the conductor to the electrodes and dissipate into the ground.

When lightning strikes the power line, the high voltage surge propagates into the substation. At that time, lightning protection devices work to conduct the lightning current along the conductors to the electrodes and dissipate into the ground.

In the event of a ground fault in a 3-phase ungrounded electrical system, the ground current (also known as the zero-sequence current) will flow through the electrodes and dissipate into the ground.

The two main components of the grounding system are the electrodes and the grounding wire.

Grounding electrodes include vertically installed electrodes or horizontally buried electrodes at a certain depth. In practice, electrodes are often made of zinc-coated steel ≥ L 50x50x5 mm or zinc-coated round steel Φ 22mm2 with a length of 2m to 3m, which are buried deep into the ground perpendicularly. The top of the electrode is 0.5m to 0.8m above the ground and is welded together with flat iron bars with a cross-sectional area of S = 40x 4 = 160mm2 to prevent chemical corrosion, avoiding using steel with a thickness less than 4mm. The distance between two electrodes is from 2m to 5m.

The grounding wire is located above the ground and is made of zinc-coated round steel Φ10 or multi-stranded copper wire with a cross-sectional area of S ≥ 25mm2. One end of the grounding wire is connected to the grounding electrodes, and the other end is connected to the parts that need to be grounded, such as lightning protection devices or electrical equipment supports, transformer enclosures, transformer neutral electrodes, etc. The cross-sectional area of the grounding wire connection should not be less than 1/3 of the phase wire.

Grounding electrode: 16×2400 copper-coated electrode + clamp, 25mm2 stranded copper wire, CU cable bolt 25(22)mm2, 2/0 clamp + 2/0 hotline, stainless steel wire 20×0.4×1.2m/strand + A20 strap lock.

II – Main tasks in the construction of a turnkey 250KVA substation:

1. Main job scope:

• Carry out all legal documents and procedures related to the installation of a 250KVA transformer station.
• Test and provide test records for materials and equipment before installation and connection of the 250KVA transformer station.
• Install a new set of measuring instruments at the branch point for measuring electrical energy for the 250KVA transformer station.
• Install a new MCCB 400A circuit breaker, protecting the low-voltage side of the 250KVA transformer station.
• Complete the construction of a 250KVA 0.4/22KV gantry transformer station.

***After signing the construction contract, Quang Anh Electrical Construction Company will be responsible for all related procedures, and the investor will only provide legal documents:

Land use rights certificate (or land lease contract) Business license Identification card (or passport) of the legal representative, commitment to environmental protection (if any)

==> Each type of document requires 03 sets with notarization no more than 03 months.

• The normal connection time for document preparation, material preparation, and gathering is 45 days. The construction time is 15 days, for a total of 60 days.

2. Please note:

The price of the gantry-type 250KVA transformer station provided here is for reference only and does not include 10% VAT, calculated based on the price of materials and equipment at the current time (January 2020), with a maximum connection distance of 40m and overhead medium voltage line.

The actual price depends on each locality or different industrial parks. It also depends on the location, connection method, distance from the connection point to the 250KVA transformer station, and the materials and equipment used for the station.

Transformer brands: THIBIDI, MIEN NAM, EMC, SANAKY, SHIHLIN, AGE, HEM, EEMC (See THIBIDI transformer prices here)

Mitsubishi, LS circuit breakers

Thinh Phat, Cadivi, LS cables

Stand insulators, hanging insulators, LA, FCO, LBFCO, and other accessories…

Professional, high-quality, and fast progress.

With a team of highly skilled engineers and electrician workers of up to 400 people on a project, Xay Lap Dien Quang Anh offers the best choice for customers with projects of all sizes regarding complete construction of 250KVA transformer substations.

This includes construction of 22KV, 35KV overhead power lines, excavation and reinstatement, underground conversion of low and medium voltage power grids, and installation of fully finished 250KVA transformer substations that require high technical requirements, safety, and fast progress.

We aim for customer satisfaction, therefore, we do not compromise on quality products and weak craftsmanship in relation to the services of Quang Anh.

With us, customers will feel the difference, with “Safety – Reputation – Quality – Progress” being the most important aspects of every project.

If you need advice or a detailed estimate for your project, please call the hotline: 0919758191.

QUANG ANH CE CO., LTD

Address: 2nd Floor, I2 Building, 236/26 Dien Bien Phu Street, Ward 17, Binh Thanh District, Ho Chi Minh City

Phone: 028 627 24787 – Hotline: 0919758191

Website: https://quanganhcgte.com/ Email: sales@quanganhcgte.com

Tax Code: 0316365712

“Saving energy is investing for future generations.”