Good quality KC500D Current Transformer Secondary Overvoltage Protector

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Place of Origin:
Brand Name:
Model Number:
Product name:
KC500D secondary overvoltage protector
Model Number::
voltage and current transfomer
Protecting Function
advanced technology, reliable components, long life

Packaging & Delivery

Selling Units:
Single item
Single package size: 
13.5X11X9 cm
Single gross weight:
0.4 kg
Package Type:
One piece in one carton.
Picture Example:
Lead Time :
Quantity(Piece) 1 - 10 11 - 20 >20
Est. Time(days) 7 15 To be negotiated

Model Specifications

Number of windings
KC500 D- 1~6
116* 90*73

1.Use and Characteristics

      Current transformer (referred to as CT) is widely used in power system for one measurement and control. When the current transformer is in normal operation, the secondary load impedance is very small, and the secondary output voltage is very low, which is equivalent to a short-circuit transformer. The full-scale current is generally 1A or 5A, the rated load capacity is 5VA-100VA, the corresponding load resistance is 0.2Ω--20Ω, and the secondary side voltage is 1V-20V. If the secondary winding is open, or an abnormal overcurrent (such as lightning current, resonant overcurrent, capacitor charging current, inductor starting current, etc.) flows through the primary winding, it will generate several thousand volts or even tens of volts on the secondary side. Voltage. This not only causes damage to the insulation of the secondary system, but also causes the transformer to be over-excited and burned, and even endangers the life safety of the operating personnel. 
      The consequences of the secondary circuit opening of the current transformer:  
● Steep wave high amplitude overvoltage seriously endangers the insulation of equipment and the safety of workers. In the past, many electric shocks have caused death and destroyed equipment accidents. 
● The current transformer core loss is too large, and the heat is severe, which will cause the transformer to be over-excited and burned. ● Remanence generated in the iron core will increase the measurement error of the current transformer and even make the secondary control protection system malfunction.
2.Working Principle

Protector action V-T diagram

3.Wiring principle

      In general, the current transformers are connected to the three phases A, B, and C, and a few are connected to the two phases, and are individually connected to one phase. Most are star connections and a few are triangle connections. The protector is a secondary winding star connection. The secondary windings A, B, and C are connected to the terminals of the protectors A, B, and C. A, B, C three-phase secondary neutral point (virtual ground N) is connected to the N terminal of the protector. If only the A and B windings are used, the C phase can be disconnected and will not affect the normal operation of the protector. (See the wiring diagram for illustration.) 
      The AC220V power supply is directly connected to the AC220V terminal of the protector. The three alarm lines have a midpoint, one is normally open, and one is normally closed. The user uses the corresponding wiring according to the actual use. The power supply of the device can also be determined according to user requirements.    
      The device provides a pair of normally open contacts and a pair of normally closed contacts with a contact capacity of AC277V/10A. It can be connected to various sound and light alarms or remote information transmitted to the integrated protection device. When the protection is activated, the normally open contact is closed and the normally closed contact is opened.

4.circuit of the current transformer

(1) Test terminals or connecting pieces in the AC current loop, due to some defects in structure and quality, the contact between the screw and the copper connecting piece screw hole is poor during operation, resulting in an open circuit; (2) The secondary line terminal joint in the secondary circuit is not tightly crimped, and when the current in the circuit is large, heat or oxidation seriously causes an open circuit; (3) Due to work errors, the repair personnel forgot to connect the relay or the internal connector of the instrument, and did not find it during the acceptance; (4) The outdoor terminal box and junction box are damp, and the terminal screws and gaskets are seriously corroded, resulting in an open circuit; (5) The test terminal press plate in the current loop is too long, and the rotating terminal metal piece is not pressed on the metal piece of the pressure plate, and the pressure is pressed on the bakelite to cause an open circuit.
5.Product technical standards and parameters
Product technical standards: 
GB/T1408-1989        Test method for power frequency electrical strength of solid insulating materials 
GB/T2423.46-1997   Environmental experiment of electrical and electronic products 
DL/T620-1997           Overvoltage protection and insulation coordination of AC electrical installations 
GB7251.1-1997         Low-voltage switchgear and control equipment 
GB1208-1997            Current Transformer Standard
Product Specifications
Normal leakage current IL20V
Input resistance
Turn-on voltage
150V±10% (factory setting, can be set with user requirements)
On time
Alarm output contact capacity
AC277V/10A; DC110V/10A
Protection relay contact capacity
Use CT specifications
Secondary side peak is greater than 150V
Protection current
Working environment
 Temperature: -20 ° C ~ +70 ° C
No more than 2000 meters
Reset moder
Manual button reset; automatic reset
Seismic performance
10-50-10HZ 2g 3min
Reliable safety
In accordance with IEC834-1 requirements
Working power supply
AC220V, 50HZ or DC220V
Power consumption
Installation method
6.Dimensional Drawing & Terminal Block Diagram
  KC500D-4 Terminal Wiring Diagram                                  KC500D-6 Terminal Wiring Diagram   
  KC500D-9 Terminal Wiring Diagram                                  KC500D-12 Terminal Wiring Diagram   






Are you manufacturer? 
Yes, we are a professional manufacturer with 15 years of experience, with our own production base and R&D team. Welcome to visit our factory at anytime! 

Warranty and return: 
Five years warranty. We own the best after-sale service team, if any problem happens, our team will do our best to solve it for you. 

Could you accept product customization orders?
Of course ,we accept OEM and ODM order. OEM: LOGO and Brand printing,product packaging and outer packaging requirements. ODM: Provide us with product technical parameters and more details. 

How about your delivery date? 
Sample is around 1-3 days in stock,no stock is around 3-5 days . Large order is around 7-15 days. Customized order is around 15-30 days.
    Anhui Kaichuan Group is located in Hefei Luyang Industrial Park with beautiful scenery and developed science and education. It is specialized in power quality optimization, over voltage and over current protection equipment, electronic control, high and low voltage complete equipment and intelligent control technology. A high-tech enterprise integrating product development, production and sales. 
     The company's several series of products are widely used in power, petroleum, chemical, metallurgy, cement, steel, copper and port industries, providing solutions for power overvoltage protection of China's top 500 companies and participating in technical support for many projects. The company has made favorable comments on the energy saving and consumption reduction of the enterprise and the reasonable layout of the system.
     The company's products have independent intellectual property rights and have passed the test of national professional institutions, which also obtained the state. Two patent technology product certificates were issued. In 2011, the company was recognized as a software company by the Ministry of Information Industry. The company has passed the ISO9001 International Quality Management System, ISO14001 International Environmental Management System and GB/T28001:2001 Occupational Health and Safety Management System. The system covers the design, Comprehensive management of supply, production, sales, logistics, technical support, after-sales service, etc., giving full play to the overall advantages of R&D, production, operation and service. At present, Kaichuan Power has core institutions such as Power Quality R&D Center, Overvoltage and Overcurrent Protection Product Center, Hefei Production and Processing Base, Marketing Center, Beijing Service and Response Center, and has several provincial offices throughout the country. The team serves and responds to the product.
     Kaichuan adheres to the "people-oriented" business philosophy, employs high-paying industry experts in the research and development of new products, optimizes product performance structure; gathers marketing elites in the construction of sales teams, practices teamwork, and always adheres to "creating first-class quality and providing The aim of “quality service and Kaichuan brand” is to continuously explore in practice, keep on advancing in exploration, and constantly innovate in the process of progress.
     "Integrity, pragmatism" is our unchanging experience! 
     “Innovation, transcendence” is our consistent strategy! 
     We are willing to work together with the industry to create a better future!
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