Product Description:

With the continuous development and progress of society, great changes have taken place in my country’s urban power grids, and most cities have formed or are forming dense areas with large power loads. The power supply from the 12/24kV line (or branch line) of the substation to the direct users in the past has been difficult to meet the urban

development requirements. As a result, a new power supply mode is generated to supply power to users through switching stations. But with the intensification of urban densification. Some original civil construction type switchgears have been restricted by land and urban planning, so a more advanced and practical outdoor intelligent switchgear (outdoor ring network cabinet) has emerged. This switchgear does not require civil engineering and occupies a small area. The configuration is very flexible and the power supply method is more reliable. The construction and installation, commissioning time are greatly shortened, and the overall cost is reduced.

With the development of modern industry, the degree of automation and intelligence of electrical control equipment is getting higher and higher. Using modern electronic technology, sensor technology, communication technology, and computer network technology, the monitoring, protection, Integration of control and measurement to achieve good management has become an inevitable trend and development direction.

The intelligent opening and closing station (outdoor ring network cabinet) adopts and learns from foreign advanced technology. 12/24kV switchgear, circuit breaker, load switch, current and voltage transformer, 12/24kV power supply PT, switching station FTU, RTU, communication control terminal (CCU), 12/24kV metering and automatic meter reading, USP power supply and Indicating instruments, etc. are installed and debugged into a movable, sealed and moisture-proof stainless steel box, thus realizing the integration and modularization of the primary and secondary systems in the urban power distribution network, and shortening the construction period. Greatly improved the reliability of urban power grid operation.

Item Meaning:

Application Condition:

• Altitude: ≤2000m
• Ambient Temperature: -25℃– 40℃/ -13℉–104℉
• Maximum Diurnal Temperature: 25K
• Relative Humidity: daily average≤95%； monthly average≤90%
• Earthquake Intensity: ground horizontal acceleration 0.2g; vertical acceleration 0.1g act at the same time. Using resonance, sine, beat wave test methods; vibrate 5 times, 5 waves each time, each interval is 2s, and the safety factor is not less than 1.67
• Installation Environment: no gas vapor, chemical deposits, dust, dirt and other explosive and corrosive media that seriously affect the insulation of the load switch; using in ungrounded systems and 10kV systems grounded through a small resistor or through a crowbar.

Structural and Technical Requirements：

• The load switch in the box-type switching station adopts a three-position SF6 load switch, and the electrical life of the SF6 load switch should meet the requirements of E3 level. The electrical life of the circuit breaker should meet the requirements of E2 level.
• Take anti-condensation measures in air-insulated switch cabinets such as PT cabinets and metering boxes (install condensation controllers in the cabinets), such as installing resistance heaters (with control switches).
• The relative pressure of SF6 in the gas bag of unitary SF6 ring main unit should not exceed 1.4bar. The entire gas-filled enclosure shall meet the requirements of a “closed pressure system” specified in IEC 60298, with an annual air leakage of not more than 1%, maintenance-free for 30 years, and no need to re-inflate. The pressure of the gas in the SF6 gas chamber can be monitored through the SF6 pressure gauge.
• The rated current of the fuse should match the load. The parameters of the fuse are: rated voltage 12kV. Rated breaking current (effective value) 63kA. Switching stations used for distribution transformer protection should be capable of both fuse tripping and electric tripping.
• The box-type switching station should have perfect five-proof interlocking function.
• Through the control of the interlocking device of the mechanism, the operation can fully achieve the following five-proof interlocking functions:

① Prevent mis-division and mis-closing of circuit breakers (load switches);

②Prevent on-load opening and closing of the isolating switch;

③Prevent charging from hanging (closing) the grounding wire (grounding switch);

④Prevent the connection and disconnection of the grounding wire (grounding switch) (load switch, isolating switch);

⑤Prevent strayed into the electrified compartment.

• Fully enclosed structure is adopted, and the switchgear is mainly composed of air chamber, cable chamber, mechanism chamber (secondary chamber) and other compartments. The distance from the cable joint to the cable entry (hole or fixing hoop) is ≥ 370mm, and the inner sleeve and supporting insulating parts are made of epoxy resin material, and the specific creepage distance is ≥ 20mm/kV. Copper busbars are used for indirect connection, and copper busbars are used for grounding busbars. The selection of section and surface should meet the requirements of GB3906.
• The panel of the mechanism box is equipped with a live indicator with the function of electric inspection, which is convenient for replacement, and can be connected with a secondary phase nuclear instrument externally.
• The imitation plate of the primary line of the box-type switching station is clearly marked;
• Internally installed high-voltage electrical components, such as SF6 load switch, circuit breaker, transformer, lightning arrester, etc., should have durable and clear nameplates, and the nameplates should be installed at positions that are easy to observe during operation or maintenance.
• The opening and closing station is equipped with a secondary room or a control box, and has a secondary circuit matched with the operating mechanism. It can be configured with manual/electric operating mechanism, and reserves electric operation function, remote control and remote signaling interface to meet the needs of remote monitoring. It should also have a short-circuit fault indicator to meet the requirements for phase-to-phase short-circuit and single-phase fault grounding indication, and has Switch value output function, the terminal inside the ring network cabinet is required to be used, dust-proof and flame-retardant products.