KYN28-12(GZS1-12) Indoor AC Metal-clad Withdrawable Indoor Switchgear 

KYN28A-12(GZS1 -12) Indoor AC metal-clad withdrawable switchgear (Hereafter referred to as”switchgear”) is an advanced medium voltage switchgear, developed by Xi’an Senyuan corporation. We had developed the miniaturization withdrawable switchgear cabinet of 650width based on their technologies. It is suitable for the applications in three-phase AC electric power system with rated voltage of 12kv and rated frequency of 50Hz, for the acceptance and distribution of the power, and also provides control, protection, and monitor of the circuit. Technical transferred is also provided by the same corporation.

1. Applicable Standards:

GB3906-2006: AC metal-clad closed switchgear and control equipment 3.6kV-40.5kv

GB11022-1999: General technical qualification of high-voltage switchgear and control equipment

IEC62271 -200/2003: AC metal-clad close switchgear and relevant control equipment with rated voltage between 1 kV and 52kv DL/T404-2007: AC metal closed switchgear and control equipment 3.6kV-40.5kv

2. Type of the Product and Their Indications

3. Technical parameters

3.1 Technical parameters of switch equipment, refer to Table 1

					Table 1
ltem		Unit	Parameter
Rated voltage		kV	3,6,7.2,12
Rated frequency		Hz	50
Rated current of the circuit breaker		A	630,1250,1600,2000,2500,3150
Rated current of the switch cabinet		A	630,1250,1600,2000,2500,3150
Rated thermal current (4s)		kA	16,20,25,31,5.40,50
Rated dynamic current (peak value)		kA	40.50.63,80,100,125
Rated short circuit drop out current		kA	16,20,25,31.5,40,50
short circuit making current (peak value)		kA	40,50,63,80,100,125
Rated insulation ability	1min power frequency withstand voltage	kV	24	32	42
	Lightening impact withstand voltage	kV	40	60	75
protection degree		P4X for shell,and IP2X When breaks room door is open

3.2 Technical parameters of VD4、 VS1-12 vacuum circuit breaker and FP series sulfur hexafluoride circuit breaker
a. Technical parameters of VD4^ VS1-12 vacuum circuit breaker and FP series sulfur hexafluoride circuit breaker, refer to Table 2

			Table 2
Item		Unit	Parameter
Rated voltage		kV	3,6,7.2,12
Rated frequency		Hz	50
Rated current of the circuit breaker		A	630,1250,1600,2000,2500,3150
Rated thermal current(4s)		kA	16,20,25,31,5.40,50
Rated dynamic current(peak value)		kA	40,50,63,80,100,125
Rated short-circuit drop out current		kA	16,20,25,31.5,40,50
Short-circuit making current (peak value）		kA	40.50.63,80,100.125
Rated insulation ability	1min power frequency withstand voltage	kV	42
	Lightening impact withstand voltage	kV	75
Rated operating sequence		kA	breah-0.3s-close breaking-180s-close breaking
Rated short-circuit current making time		time	50
Mechanical life		time	20000

b.  Mechanical feature of VD4、VS1 vacuum circuit breaker and FP series sulfur hexafluoride circuit breaker, refer to Table 3

			Table 3
Item		Unit	Parameter
Switching distance of the contact		mm	11±1
Contact exceed range		mm	4±0.5
Center distance between phases		mm	150±0.5,210±0.5,250±0.5,275±0.5
Closing contact bounce time		ms	<2
Different period of three-phase break	brake	ms	<2
break brake time when voltage	Max	ms	<50
	Rated	ms	<50
	Min	ms	<60
Making time		ms	C100
Average opening speed		m/s	0.9-1.2
Average opening speed		m/s	0.6-0.8
Circuit direct current resistance of each phase		0	<40
Contact pressure		N	3200±100

When the circuit breaker is applied to control 3-1 Okv electromotor, AC 600A, a metal-oxide surge arrester must be installed;clients can consult with manufacturer for the detailed requirements. When the circuit breaker is aplied to cut off the capacitor the group, the rated current of capacitor group should not be the circuit breaker.

3.3 Technical parameters of operation mechanism, refer to Table 4

Item		Unit	Value
Rated operation voltage	Closing coil	V	DC220.110 AC220,110
	Opening coi	V	AC220.110DC220,110
Coil power	Closing coil	W	245
	Opening coil	W	245
Power of energy storage motor		W	50
Rated voltage of energy storage motor		V	DC220,110,AC220,110
Time of energy storage		S	<10

4. Structure

A-Busbar room                                 B-Circuit breaker handcart room                       C-Cable room

D-Relay instrument room                 1- Shell                                                               2- Branch busbar

3- Busbar bushing                              4- Main busbar                                                  5- Static contact box

6- Static contact                                 7- Current transformer                                       8- Earthing switch

9- Cable                                             10- Arrester                                                        11- Earthing main busbar
12- Removable clapboard                 13- Separator (Valve)                                         14- Secondary plug

15- Circuit breaker handcart              16- Heating device                                            17- Withdrawable horizontal baffle plate

18- Operation device of earthing switch 19- Secondary trunking                        20- Soleplate

21- Pressure release device

Figure 2. After the draw-out circuit breaker is moved, the static contact in the separate room will be shielded by the metal valve, the circuit breaker will be protected.

Figure 3. In the separate room of the circuit breaker, open the metal valve to check the static contact.

Structure overview

The switchgear is designed according to GB3906 metal-clad closed switchgear. It composes of a main body enclosure and a withdrawable component (called handcart). The enclosure is divided into four separate rooms. The protection lever of the shell will be IP4X, and if the door of separate room or breaker room is open, then the protection lever should be IP2X. There are several functional schemes such as overhead inlet and outlet overhead line, inlet and outlet cable, forming a whole electric power distribution system device. This switchgear can be installed, commissioned and maintained from the front, which makes it possible to be arranged as back-to-back, side-to-side, or against the wall.

4.1 Shell and auxiliary
The main body enclosure formed by import zinc steel plate coated with aluminum, double-bented by CNC machine. Owning to this advance process, the cabinet gains less weight, higher mechanical strength and more artistic outward appearance compared with other products, as well as the advantage of higher precision, strong anti-corrosion and anti-oxidation capacity. The cabinet adopts assembling configuration. It is connected with high intention nuts and bolts, thus the process manufacture period is shortened, while occupying less area, the components are highly optimized for general use, so it is easier for organization.

4.2 Handcart

The framework of handcart, alike the cabinet, is formed by steel plate, and processed by CNC machine. The handcart is insuloted from the cabinet when combined. The mechanical interlock is safety, reliable and flexible. Based on the different usage, there are circuit breaker handcart, potential transformer handcart, measure handcart and separate handcart. All kinds of handcart can be organized on basis of modulus. The same type of handcart can be replaced. In cabinet, handcart may be at break position, testing position, or working position, each one has its own locating device to ensure reliable interlock followed by the operation procedure to prevent interlock disoperation. All handcarts are fixed by nut or spindle, so the operation is convenient and flexible for all operators. The handcart can be easily drawn out from the cabinet for inspection and maintenance. Due to the withdrawable adoption, it saves space and is easily to be inspected and repaired.

4.3 Separate room

Each main electric unit has a separate room, that is, circuit breaker handcart room, busbar room, cable room and relay control room.All the rooms can achieve IP2X protection level. Except for the relay control room, the other three separate rooms are equipped with a release pathway. Owning to the withdrawable type, the increased cable room enable the multiple cable are connected.

4.3.1 Circuit breaker room

There is one slide guide at each side of the circuit breaker room for the handcart [15] to move from breaking position or testing position to operation position. The separator (Valve) [13] of the static contact [6] is installed on the back of the handcart room. When the handcart [15] is moving from the breaking or testing position to the operation position, the up and down valves of the static contact connecting with the handcart would be open automatically. On the contrary, when moving opposite to cover the static contact, the valves would close automatically. Since the up and down valves could be operated separately, the operator would not touch the live parts during the maintenance while the live parts are separated. When the circuit breaker room is closed, the handcart can be handled as well. Moreover, the handcart status and the energy storage can be monitored through the middle inspection window.

4.3.2 Busbar room

The main busbar [4] in Figure 4, is consist of single busbar and fastened by branch busbar [2] and static contact box [6]. The main busbar [4] and interbus are rectangular cross section copper busbar which are used for large current load by double busbars. The branch busbar is connected to the static contact box [6] and main busbar [4] through bolt. For special requirement, the busbar can be wrapped with heat-shrinkable bushing, link bolt insulation sleeve and end cap. Adjacent busbars are fixed with bushing [3]. If there is an Internal fault arc, the space between the busbar can be used as air buffer to prevent from melting. Thus the bushing [3] is quite necessary to ensure the safety and stops the accident spreading to other parts.

4.3.3 Cable room

The cable room has a large space since the switchgear employs mid-set switch type. The current transformer [7] and earthing switch [8] are installed on the back of the room, and arrester [10] is on the bottom back of the room. The workers could access the inner cabinet for installation and maintenance by moving away the handcart [15] and withdrawable horizontal plate [17]. Cables in the Cable room are connected to the conductoi Each phase can be linked with 1 to 3 single cores cable, or 6 single cores when necessary. The removable non-metal panel or non-conductive metal plate is equipped to ensure the construction conveniently.

4.3.4 Relay Control room

The relay control room is equipped with relay protection device, instrument, powered monitoring indicator and specialized secondary equipment. All the control lines are placed in the trunking with enough space and covered by metal plate, isolating the secondary line from HV chamber. The left side trunking is used for reserved circuit lines incoming or outgoing. Lines internal from the switchgear itself are placed in the right trunking. On the top of the relay control room plate, there is a reserved little hole for busbar installation. Moreover, the top plate can be turned over for busbar installation.

4.4 Interlocking device to prevent fault operation

Switchgear is equipped with reliable interlocking device, satisfying the “Five Standards** .

a. There is an obvious button or KK type alternation switch to prevent fault operation.

b. Only when the circuit breaker handcart is under test or operation site, the circuit breaker can be used to switch on or switch off. In addition, the handcart is not able to move while the circuit breaker is switched on. It helps to stop on-load wrong operation.

c. Only when the earthing switch is on the breaking site, the circuit breaker handcart is able to be moved from the breaking or test site to operation site. Only when the circuit breaker handcart is on the test or breaking site, the earthing switch can be switch off (the earthing switch can be fitted with voltage indicator). Thus it helps to avoid switching off the earthing switch when under hot line, as well as switching on the circuit breaker when earthing switch is on closed site.

d. In order to prevent the staff access to the area, the bottom door and back door cannot be open when the earthing switch is on breaking site.

e. When the circuit breaker handcart is located on the test or operation site without control voltage, it can only be operated by manual mode, not automatic mode.

f. When the circuit breaker handcart is on the operation site, secondary plug is locked and not able to be pulled out.

g. Electric interlock is applied for each cabinet.

The switchgear can be equipped with electromagnet locking device on the earthing switch to improve reliability. Customers choose whether they need it or not.

4.5 Pressure relief device

There are pressure relief devices installed in the circuit breaker room, busbar room and cable room. When the inner fault occurs with arc, pressure inside the cabinet will increase. Then the special preassemble gasket on the door seals the cabinet in the front. Finally the pressure relief device on the top open automatically to release the pressure, ensure the safety of operator and switchgear itself.

4.6 Secondary plug and handcart interlock

The secondary circuit of switchgear and handcart are interlocked through manual secondary aviation plug. Moving-contact from secondary plug is connected with circuit breaker handcart by nylon corrugated expansion pipe. The secondary static contact base is fixed on the top right of the handcart. Only when the handcart is set on the test or breaking site, the secondary plug can be plugged in or pulled out. When the circuit breaker handcart is on the operation site, the secondary is locked and cannot be pulled out since the function of mechanical interlock works. As the closing mechanism of circuit breaker handcart is locked by the electromagnet, the handcart is only able to be switched off when the secondary plug is disconnected.

4.7 Charged display device

There is a charged display device for testing the primary circuit if customer requires. This device consists of high pressure sensor and portable display. They are connected together with wires as a whole. It not only shows the high pressure circuit status, but also can be cooperated with electromagnetic lock to force earthing switch handle and net door locked. This manner helps to prevent switching off earthing switch with live and accessing into the live zone, to avoid faulty operation.

4.8 Condensation and corrosion prevention

In order to avoid danger when operating in the high humidity and large fluctuations temperature, heater is installed in the circuit breakerroom and cable room separately, to prevent corrosion in above environment.

4.9 Earthing device

There is an individual earth copper busbar with a dimension of 5X40mm2 in the cable room which is going through adjacent switchgear, and has a good contact with the switchgear body. This busbar is used for components that are earthing directly. Meanwhile, since the whole switchgear body is made up of aluminum zinc plate, it makes a good earthing status to protect the operator and switchgear.

4.10 Switchgear overall dimension (refer to Figure 6 and Figure 7)