Overview

The LXK-120 Open-type Zero Sequence Current Transformer is Indoor Cast Resin, and is designed with a split structure, made of resin cast into a semi-circular shape and connected by a clamping ring. During installation, the transformer can be separated into two halves and then combined back into one unit, making installation extremely convenient. The LXK-φ80(100,120) Zero Sequence Current Transformer is suitable for use in power systems with rated frequencies of 50Hz or 60Hz for zero-sequence relay protection.

This product features a cable-through-core structure for the primary circuit, so only the insulation of the secondary coil needs to be considered. The secondary coil has a 3kV withstand voltage for power frequency. The common models in this series include: LXK-φ80, LXK-φ100, LXK-φ120, LXK-φ150, and LXK-φ180.

The LXK-120 Zero Sequence Current Transformer is specifically used for overcurrent protection in power systems, high-voltage three-phase AC generators, and motors in 10kV and below, 50Hz lines, primarily for indoor use. The outer diameter of the transmission cable should not exceed 120mm. For detailed dimensions of models LXK-80 to LXK-160, please refer to the technical parameters table.

Type Description of LXK-120 Zero Sequence CT

• L: Current transformer
• X: Zero-sequence
• K: Open-close type
• Φ120: Nominal diameter of the inner hole

Working Principle

The zero-sequence current transformer works in conjunction with relay protection devices or signaling systems when a zero-sequence ground current is generated in the power system. This enables the device components to act, achieving protection or monitoring functions.

The LJK and LXK series zero-sequence current transformers are cable-type transformers with ABS engineering plastic housings and fully sealed resin casting. They use an insulated oil cooling cutting process to effectively prevent rust during long-term operation. These transformers feature excellent insulation performance, an attractive appearance, high sensitivity, good linearity, reliable operation, and easy installation.

Their performance surpasses that of general zero-sequence current transformers, making them suitable for a wide range of applications. They can be used not only for electromagnetic relay protection but also for electronic and microprocessor-based protection devices. Users can select the appropriate zero-sequence current transformer according to the system’s operating mode, whether the neutral point is effectively grounded or non-effectively grounded.

Technical Data of LXK Open-type Zero Sequence Current Transformer

The products accord with the standards of GB20840.1-2010, GB20840.2-2014, and some special demands.

• Rated insulation: 0.72/3 kV
• Rated frequency: 50Hz/60Hz
• Rated secondary current: 5A or 1A
• Ambient temperature: -25°C ~ +40°C

Type	Classes	Rated Current Ratio (A)	Rated Output (VA)
L XK-80 (80/165*57)	10P5 ~ 10P10	50/5 75/5 100/5 150/5 200/5 250/5 300/5 400/5 50/1 75/1 100/1 150/1 200/1 250/1	5 ~ 1
LXK-100 (100/180*55)	10P5 ~ 10P10		5 ~ 1
LXK-100 (100/180*57)	10P5 ~ 10P15		10 ~ 1
LXK-120 (120/204*57)	10P5 ~ 10P15		10 ~ 1
LXK-120 (120/210*65)	10P5 ~ 10P15		10 ~ 2.5
LXK-120 (120/210*100)	10P5 ~ 10P20		15 ~ 2.5
LXK-120 (120/250*80)	10P5 ~ 10P20		15 ~ 1
LXK-150 (150/235*57)	10P5 ~ 10P10		10 ~ 1
LXK-150 (150/280*80)	10P5 ~ 10P20		15 ~ 1
LXK-160 (160/250*80)	10P5 ~ 10P20		5 ~ 1
LXK-180 (180/265*57)	10P5 ~ 10P10		10 ~ 1
LXK-180 (180/310*80)	10P5 ~ 10P20		15 ~ 1
LXK-200 (200/330*80)	10P5 ~ 10P20		15 ~ 1
LXK-240 (240/350*80)	10P5 ~ 10P20		15 ~ 1
LXK-260 (260/370*80)	10P5 ~ 10P20		15 ~ 1.5

Note: If the requested data, including current ratio or installation dimensions, exceed the specified ranges mentioned above, they may be subject to negotiation and agreement between the manufacturer and the purchaser.

Installation and Maintenance

 

Type	Φd	ΦD	C	a	b	A	B	E	L	f	h
LZX-80	80	165	57	110	60	130	120	102	185	10	17
LZX-100	100	177	55	110	90	130	118	114	203	10	17
LZX-100	100	180	57	110	90	130	120	113	223	10	17
LZX-120	120	204	57	110	90	130	120	121	223	10	17
LZX-120	120	210	65	110	100	125	125	123	228	10	17
LZX-120	120	210	100	110	133	130	163	123	228	13	23
LZX-160	160	250	80	150	125	190	174	153	268	13	23
LZX-150	150	235	57	150	125	190	174	158	297	13	23
LZX-150	150	280	80	150	140	190	174	158	297	13	23
LZX-180	180	265	57	150	125	190	151	165	298	13	23
LZX-180	180	310	80	220	125	220	164	190	365	13	23
LZX-200	200	330	80	220	125	220	164	190	365	13	23
LZX-240	240	350	80	220	125	220	164	229	395	13	23
LZX-260	260	370	80	220	125	220	164	229	410	13	23

Note: The dimensions marked with letters (e.g., Φd, ΦD, C, etc.) in the product images correspond to the values listed in the table. For further clarification or customizations, please contact our technical team.

Ordering Instructions

1. Product Model and Quantity: Please specify the model and quantity of the product you wish to order.
2. Size of the Hole: The size of the perforation is critical. Ensure to provide accurate measurements to meet your requirements.
3. Current Ratio and Accuracy: Indicate the required current ratio and accuracy for the product.
4. Custom Requirements: If a more precise current ratio or specific hole spacing is required, please contact us for confirmation and customization.

Note: Our company is a professional enterprise with many years of experience in manufacturing complete accessories. We integrate development, production, and sales, and are one of the leading manufacturers of current transformers, voltage transformers, zero-sequence current transformers, current-limiting reactors, and discharge coils both domestically and internationally. We warmly welcome your inquiries and orders.

FAQs for LXK-120 Zero Sequence Current Transformer

1. What are the primary applications of the LXK-120 Zero Sequence Current Transformer?
   The LXK-120 is primarily used for zero-sequence relay protection in 10kV or lower power systems, including high-voltage AC generators, motors, and indoor distribution systems.
2. How does the split structure simplify installation?
   The transformer can be separated into two halves, allowing it to be installed around existing cables without the need for disassembly of the primary system.
3. What customization options are available for the LXK-120?
   Customizations include tailored hole diameters, current ratios, and accuracy classes to meet specific operational requirements.
4. Is the LXK-120 suitable for outdoor applications?
   No, the LXK-120 is designed for indoor use. For outdoor applications, alternative models with appropriate insulation and protection would be required.
5. What precautions should be taken during operation?
   Ensure the secondary circuit is closed during operation to avoid generating high voltages. Regular inspections are recommended to maintain cleanliness and ensure reliable performance.
6. What standards does the LXK-120 comply with?
   The LXK-120 complies with GB20840.1-2010 and GB20840.2-2014 standards, ensuring high-quality performance and reliability.

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