ZW20-12 Type Outdoor High Voltage Vacuum Circuit Breaker

Short Description:

ZW20-12 outdoor AC HV vacuum boundary circuit breaker (hereinafter referred to as the boundary circuit breaker) is one of our new products. Boundary circuit breaker is a multifunctional intelligent device with the function of vacuum breaker, vacuum load switch, recloser, sectionalizer four switches. The main configuration consists of vacuum breaker, CH-40 controller, external voltage transformer (Note: distribution automation line ring network available in bilateral PT) three parts. Products are widely used in 10kV, 13kV city, rural power grid space ring network for disconnecting switch, contact switch, automatic switch device which can implement the ring deployment line load. It can be used as boundary switch (commonly known as watchdog) in the branch line of power supply, used as reclosers and sectionalizers in feed overhead distribution network. Boundary circuit breaker with remote management pattern, protection and control functions and communication functions. Reliable detection in judgment, mA level zero sequence current and shortcircuit current between phases, realize the automatic removal of single-phase grounding fault and phase to phase short circuit fault. The main switch is vacuum arc and insulation adopts SF6, N2 mixed gas. The case introducting of Japan, Germany, French gas sealing, explosion proof, insulation system technology, the overall excellent sealing performance. Inside is filled with SF6, N2 mixed gas which does not leak, not affected by the external environment. The spring operating mechanism with miniaturization and performance optimization design, action reliability is much higher than the traditional spring mechanism.

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ZW20A-12F/T Outdoor High-voltage AC Vacuum Boundary Circuit Breaker (hereinafter referred to as “boundary circuit breaker”) is a new intelligent product developed based on ZW20A-12 circuit breaker, it is mainly provided with vacuum circuit breaker body, MGK-15T controller and external voltage transformer, widely used as breaking isolation switch and interconnection switch in 10kV urban and rural distribution network overhead ring network line for breaking isolating switch and interconnection switch, realizes load deployment of ring network line, used as the boundary switch (also called “watchdog”) in the power supply branch line of big user and has the protection control and communication functions. It can judge and detect the milliampere zero-sequence current and inter-phase short-circuit fault current in the industry, and cut off single-phase grounding fault and inter-phase short-circuit fault automatically.
The switch body uses vacuum arc extinguishing and SF6 gas insulation. The box has good sealing performance and can be filled with SF6 gas without leakage and external environmental influence. The performance of spring operating mechanism is optimized, and the action reliability is superior to traditional spring mechanism.

Environmental conditions for service:
1).Altitude: ≤2000m
2).Ambient temperature: outdoors: -30℃ – +55℃
Highest annual average temperature: 20℃
Highest daily average temperature: 30℃
Maximum daily temperature difference: 25℃
3).Relative humidity: 95% (25℃)
4).Anti-seismic capacity: Ground horizontal acceleration: 0.3g
Ground vertical acceleration: 0.15g
Act on three sine waves simultaneously and continuously
Safety factor: 1.67
5).Seismic intensity: 7°
6).Sunlight intensity: (when wind speed is 0.5m/s): 0.1W/cm2
7).Maximum wind speed: 34m/s
8).Maximum icing thickness: 10mm
9).Installation position: user responsible boundary points of outdoor 10kV overhead line
10).Grounding mode: neutral non-grounding, grounding through arc-extinguishing coil and low-resistance grounding.

Product structure and working principle:
The boundary circuit breaker is optimized and improved based on ZW20A-12 vacuum circuit breaker (see operation instruction of ZW20A-12 outdoor high-voltage AC vacuum circuit breaker), composed of external voltage transformer and MGK-15T intelligent controller and realizes electrical connection through full-sealing waterproof aviation connector and outdoor sealing cable.
The boundary circuit breaker is provided with CTA-IV spring operating mechanism and has the functions of manual/electrical energy storage, opening and closing.
There is a zero-sequence CT (transformation ratio: 20/1; 0.1-5A (primary current) section keeps the linear relation; rated load: 1Ω) in boundary circuit breaker, the transformation ratio error under rated load shall be less than 3%, the primary zero-sequence current is 400A, and the effective value of secondary output current is no less than 5A. Rated short-time withstand current 16kA, 20kA, 25kA, 4s.
There are two single-phase CTs (transformation ratio: 600/5; rated load: 10Ω; precision: 10P20; rated short-time withstand current: 16kA, 20kA, 25kA, 4s) in boundary circuit breaker.
The boundary circuit breaker has an external PT (transformation ratio: 10000/220V; capacity: 300VA; precision: Level 3P) installed on the power supply side, and the operational power supply and voltage signal of controller and circuit breaker are supplied by PT.

Functions of boundary circuit breaker:

Automatic cutting of single-phase grounding fault	When the branch line of user has single-phase grounding fault, the boundary circuit breaker will be opened automatically, so that other branch users on the substation and feeder are not affected by the fault
Automatic isolation of inter-phase short-circuit fault	When the branch line of user has inter-phase short-circuit fault, the boundary circuit breaker will be opened automatically and the fault line will be isolated automatically, so that the users of other branches on the feeder are not affected
Quick positioning of fault points	After the protection of boundary circuit breaker acts due to branch line fault of user, only the responsible user suffers outage and reports the fault information actively, and the power company can send personnel to the site rapidly for troubleshooting; If the boundary circuit breaker has communication module, information will be reported to the Power Management Center automatically
User load monitoring	The boundary circuit breaker can be provided with wired/wireless communication accessories, transmits monitoring data to the Power Management Center and realizes remote real-time data monitoring for the users.

IV. Main technical parameters
Main Technical Parameters Table (Table-1)

S/N	Item	Unit	Value
01	Rated voltage	kV	12
02	Rated frequency	Hz	50
03	Rated current	A	630、1000
04	Rated short-circuit breaking current	KA	12.5、16、20、25
05	Rated peak withstand current (peak)	kA	31.5、40、50、63
06	Rated short-time withstand current (4s)	kA	12.5、16、20、25
07	Rated short-circuit making current (peak)	kA	31.5、40、50、63
08	Mechanical life	Time(s)	10000
09	Breaking times of rated current	Time(s)	10000
10	Breaking times of rated short-circuit breaking current	Time(s)	30
11	Power frequency withstand voltage (1min): Inter-phase, over the ground/fracture	kV	42/49
12	Lightning impulse withstand voltage (peak) inter-phase, over the ground/fracture	kV	75/85
13	Secondary circuit power frequency withstand voltage for 1min	kV	2
14	Net weight	kg	140

Mechanical characteristic parameters（Table-2）

S/N	Item	Unit	Value
01	Clearance between open contacts	mm	9⁺¹ _-0.5
02	Contact over stroke	mm	3⁺¹ _-0.5
03	Opening speed	m/s	1.2±0.2
04	Closing speed	m/s	0.6±0.2
05	Closing and bounce time of contact	ms	≤2
06	Inter-phase center distance	mm	135±1.5
07	External electrified air insulation distance	mm	240±2
08	Specific creepage distance	cm/kV	3.8
09	Three-phase and non-synchronism of opening	ms	≤2
10	Conducting circuit resistance of each loop	uΩ	≤150
11	Closing time	ms	≤45
12	Opening time	ms	≤45
13	Rated power of energy storage motor	W	≯40
14	Rated voltage of energy storage motor	V	AC220
15	Rated voltage of closing operation	V	AC220
16	Maximum/minimum voltage of closing operation	V	AC264/143
17	Rated voltage of opening operation	V	AC220
18	Maximum/minimum voltage of opening operation	V	AC264/143
19	Maximum/minimum motor voltage	V	AC242/187
20	SF6 rated gas pressure (gauge pressure)	MPa	“0”