Partial discharge test shielding room

1Hzpbs-vPartial discharge test shielding roomDesign and construction basis

GB-T 12190 Measurement Method for Shielding Efficiency of Electromagnetic Shielding Room

GB50205 Acceptance Standard for Construction Quality of Steel Structures

GJB20219 General Technical Requirements for Shielding Machine Room Testing

GB/T 51103 Code for Construction and Quality Acceptance of Electromagnetic Shielding Room Engineering

GB50174 Design Code for Electronic Computer Room

GB 9361 Computer Site Support Requirements

GB/T2887 General Specification for Computer Sites

Technical requirements and measurement methods for electromagnetic shielding of confidential information processing in BMB3

GB50116 Design Specification for Automatic Fire Alarm System

Relevant principles of electromagnetic compatibility technology and current regulations on national guarantees

IIHzpbs-vPartial discharge test shielding roomMain technical indicators of the system (including dimensional errors of ± 1%)

Overall dimensions of the shielding room: length 7 meters, width 5 meters, height 4 meters

Overall dimensions of the control room: length 3 meters, width 2 meters, height 4 meters

Manual double opening rotating platform screen door opening size: width 2 meters x height 3 meters, 1 leaf (for sample entry and exit, with door interlock)

Manual single lock screen door size: width 0.9 meters x 1.9 meters, 1 leaf (for personnel entry and exit)

Control room small door (unshielded) size: width 0.9 meters x height 1.9 meters, 1 door (for personnel entry and exit, with door interlocking)

Insulation floor size: 7.5 meters long x 5.5 meters wide (without excavation)

Shielding performance (measured at 1 meter inside the gate)

Magnetic field: ≥ 60dB at 10KHz-100KHz Electric field: ≥ 60dB at 100KHz-1GHz

Partial discharge background noise ≤ 1pC under no-load test circuit conditions

Partial discharge test main circuit equipment filter: 380V/63A/2P 1-channel

Instrument power supply filter: 220V/16A/2P 1-channel

Lighting/air conditioning power filter: 220V/32A/2P 1-channel

Mechanical performance of shielding shell: steel plate unevenness ≤ 4mm/M2, shielding body verticality ≤ 5mm

Deformation degree within two years: top depression ≤ 8mm, bottom depression ≤ 3mm

3、 Design and installation plan for shielding system

3.1 Overall design scheme of shielding room shielding system

3.1.1 Shielding shell

The shielding shell is the foundation for ensuring the shielding performance of the shielding room, and is the carrier of decorative materials and most ancillary systems. It is a very basic component of the shielding room, which requires the walls of the shielding room to have sufficient strength and stability. After calculation, the overall theoretical weight of the shielding room is about 4 tons, and the workshop floor is required to withstand a pressure of about 110 kg/m2 (this weight does not include personnel, equipment, test samples, transportation vehicles, and others). The service life of the shielding body is 20-30 years, and the seismic grade of the shielding shell is calculated according to level 8.

Taking into account the load-bearing capacity of the bottom layer, the design life, cost, and production process of the shielding room, as well as the structural strength of the steel plates, the top plate and wall shielding modules of the shielding room are made of 2mm thick galvanized steel plates, which are made through processes such as shearing, punching, bending, and stress treatment. During assembly, it is fixed with galvanized bolts, nuts, and washers, and assembled by sandwiching conductive pads in the middle. The side wall shielding module adopts a self-supporting structure. In order to reduce the sinking of the middle part of the top of the shielding body, several channel steel reinforcement beams are installed above the top to effectively reduce the deformation of the top steel plate.

The bottom of the shielding room is made of 3mm steel plate, which is cut and formed into units that are spliced into standard modules. Attach and rivet the steel plate onto the keel frame, and weld the ground keel with square tubes or other types of steel; After completion, the surface should be treated with rust prevention.

Schematic diagram of shielding room and isolation area plan,

Figure 1 Schematic Plan of Shielding Room and Isolation Area

Figure 2 Three dimensional schematic diagram of the shielding room for reference

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Figure 3 Physical picture of the shielding room (integrated protective wall panel decoration on the exterior wall of the shielding room, and spray coating treatment on the interior wall)

Bottom design of shielding room

Due to the long-term bearing of certain loads on the bottom of the shielding room (such as equipment handling, product entry and exit, etc.), in order to reduce the unnecessary vibration and deformation of the floor shielding body, the bottom of the shielding room is made of 3mm steel plate and square tube keel. The workshop floor is designed to withstand a force of 600kg/m2.

The insulation floor adopts an isolation layer composed of 5mm PP insulation board welded together. The size of the insulation floor is 7.5 meters long and 5.5 meters wide. The insulation resistance between the test area and the outside world is required to be above 10k Ω, ensuring that the entire test system has no electrical connection with the workshop and preventing interference signals from other electrical equipment in the production workshop from being transmitted to the surface or underground metal parts (such as steel bars) in the test area through electrostatic coupling, and then transmitted to the test circuit through the ground wire.

Design of Shielding Room Wall

Shielding wall is a hexahedral structure composed of continuous splicing of shielding modules. The wall shielding module is made of galvanized steel sheet and rectangular tubular steel, and can support itself.

Design of the top structure of the shielding room

The top structure of the shielding room is made of 2mm galvanized steel plate to form shielding modules, and the top plate of the shielding room is installed above the inner side of the side plate. In order to distribute the weight of the shielding body and reduce the sinking of the middle part of the top of the shielding body, several reinforcing beams are installed above the top to effectively reduce the deformation of the top steel plate and ensure that the sinking of the top is ≤ 8mm within two years.

Design of Shielded Room Doors

Manual double opening rotating platform screen door size: width 2 meters x height 3 meters (one door, sample in and out)

1. The structure adopts hinge rotation, and both left and right door leaves are rotating. The door is equipped with internal and external handles, and the opening force of the door is 150N. The single-layer electromagnetic sealing plate is made of beryllium bronze material and processed into shape. After vacuum heat treatment, it achieves good elasticity and wear resistance. The shielding sealing sheet is detachable, with each section measuring 190mm in length. If there is any damage in the local area, it is easy to replace and does not require professional maintenance.

2. The door leaf has been closed and operated 10000 times without mechanical failure, and the shielding efficiency index has not decreased.

3. When closing the platform screen door, first close one door and fix it with a pin, then close the other door. The joint between the left and right door leaves should also be sealed with beryllium bronze for shielding treatment.

4. The threshold height of the platform screen door is about 50mm.

The door is equipped with a power control switch for entering and exiting the door. After the door is closed, it can be closed for testing. In the experiment, once the door is opened, the internal power is automatically cut off.

Manual single lock screen door net size: width 900mm x height 1900mm (one door, personnel entering and exiting)

The shielding room door is a very important part that affects the shielding effect of the entire shielding room. It is a weak component that maintains the overall performance of the shielding system from degradation and is also a separately movable part of the system. Therefore, maintaining the stability of the shielding effectiveness of the shielding door is particularly important.

(1) The structure adopts hinge rotation, blade type manual shielding door, dual point locking mechanism, double-layer electromagnetic sealing gasket, and the sealing gasket is made of beryllium bronze material processed and formed to achieve good elasticity and wear resistance after vacuum heat treatment. The shielding sealing sheet is detachable, with each section less than 198mm in length. If there is any damage in the local area, it is easy to replace and does not require professional maintenance.

(2) The blade of the plug-in shielded door is made of brass plate.

(3) Due to the fact that the sealing plate and its contact part (the blade of the shielding door) are made of the same material and have the same potential difference, there will be no electrical corrosion at the contact points, ensuring long-term shielding effectiveness.

(4) The locking device is installed on the upper part of the door frame, and a double point wedge locking mechanism is installed on the left side of the door frame. The operation of the wedge seat frame adopts a roller groove structure.

(5) The locking operation device is installed in the middle of the door panel, and its gear mechanism greatly reduces the force of opening the platform screen door. A double point wedge locking mechanism is installed on the left side of the door frame, and the operation of the wedge seat frame adopts a bearing groove structure, which runs smoothly and lightly.

(6) The locked platform screen door is designed to be interlocked and can be operated both indoors and outdoors.

Manual door materials: ordinary brass and beryllium bronze.

3.1.2 Grounding system

The grounding system of the shielding room adopts a separate grounding method from the grounding system of the factory power grid, that is, a single point grounding with insulated floor isolation and a separate grounding electrode. Require grounding resistance not to exceed 1 Ω. (The ground wire is the responsibility of the purchaser, and the supplier provides technical support)

3.1.3 Cut off waveguide window and ventilation system

This scheme uses two waveguide windows with hexagonal waveguide dimensions of 300 × 300, hole spacing of 4.2mm, and cutoff frequency of 20GHz.

Install forced ventilation at the position of the cutoff waveguide window to achieve air exchange between the shielded indoor and outdoor areas. The entire shielding room adopts a method of 1 inlet and 1 outlet. Installed in the control room.

3.1.4 Shielded indoor power distribution and lighting system

Principles of Electrical Design and Construction:

According to the requirements for the use of shielded rooms and relevant national design standards, fully considering the nature and tasks of the system operation inside the shielded room, the design principles are based on the quality, reliability, and technical aspects of power supply and distribution, as well as the comfort of personnel working environment.

Select power cables of appropriate wire diameter and power filters of different capacities according to the size of the electrical load of each device; Select a power filter with low leakage current, and ensure that the insertion attenuation is consistent with the overall efficiency of the shielding chamber; The indoor power supply adopts conduit wiring and power sockets are configured at the required locations.

Three phase Yyn0 connection can output 380V and 220V voltage to meet the needs of different devices.

The power supply entering the shielding room through the filter needs to pass through the wall of the shielding room, and the structure of the shielding tube passing through the wall should be made according to the requirements of Figure 4.

Figure 4 Schematic diagram of shielding tube passing through the wall

The power supply is transmitted to the shielded indoor lighting and various electrical equipment through the power filter and distribution cabinet.

According to the usage requirements, install a distribution box (PZ30-8~10P) at an appropriate position in the shielding room, with one built-in power circuit breaker for equipment (380V/63A), one power circuit breaker for instruments (220V/16A), and one power circuit breaker for lighting/air conditioning (220V/32A).

Two lighting switches (two combination type, separate control of control room lights and test area lights), three 2+3 sockets (10A) for the test area power supply, one dedicated socket (16A) for the control room air conditioning power supply, and two 2+3 sockets for other electrical power supplies. The specific installation location will be determined on site.

Install 6 lamps without electromagnetic interference on the top of the shielding room, including 5 lamps in the test area and 1 lamp in the control room. The supplier shall reasonably determine the gap between the lamps based on the installation height. Ensure the uniformity of indoor light shielding.

3.1.5 Interior Decoration

Decoration Design Basis

GB/T2887 General Specification for Computer Sites

GB50174 "Design Specification for Electronic Information Room"

GB/T9361 "Requirements for Site Support of Computing Stations"

GB50222 "Code for Fire Protection Design of Interior Decoration of Buildings"

Computer room floor and actual situation on site

Selection of main materials for decoration

According to the interior decoration requirements of the "Code for Design of Electronic Computer Room", the selected materials should be flame retardant or flame-retardant

1. Top: spray coating treatment;

2. Wall surface

Outdoor wall: decorated with high-quality clean panels; See Figure 5.

Indoor wall surface: spray coating treatment; See Figure 6.

Ground: brushed with anti rust paint; See Figure 6.

control room

Control room size: 3 meters long x 2 meters wide x 3.5 meters high. The control room faces the test area and is equipped with 2 sets of 700mm (height) x 1000mm (length) observation windows. The observation windows are made of transparent 5mm+5mm thick tempered glass with stainless steel mesh, as shown in Figure 7. The control room partition is made of high-quality clean panels, and is equipped with a personnel access door with dimensions of 900mm in width and 1900mm in height. The door is equipped with a power control on/off switch for access. After the door is closed, it can be closed for testing. If it is opened during the test, the internal power will be automatically cut off.

Figure 5 Outdoor high-quality clean board decoration

Figure 6 Indoor spraying treatment+floor painting with anti rust paint

Figure 7 Observation Window

Indoor electrical lighting system

1. The work area is illuminated with non electromagnetic interference lighting fixtures.

2. Lighting control adopts switch box and switch control.

3. Install switches and sockets in the shielded room, and arrange the lighting switches, sockets, quantity, and location reasonably to ensure that the illumination meets the requirements.

4. The wall mounted air conditioner in the experimental area shall be provided by the purchaser and installed during the supplier's construction period. It shall be placed in a location that does not affect the equipment, and the specific details shall be agreed upon by both parties.

4、 Cooperation matters between both parties

1. The location of the shielding room must be jointly negotiated by both parties, and the location of the shielding room on the buyer's site should try to avoid large strong interference sources for more than 50 meters.

2. The supplier shall dispatch personnel to complete the production of the shielding room and the bottom insulation floor.

3. The supplier shall provide tools and equipment that cannot be carried by the supplier during the on-site construction, installation, and commissioning process, such as welding machines, oxygen acetylene, lifting equipment, as well as other materials such as equipment connection power lines.

4. The purchaser shall lead the power cord to the location of the partial discharge shielding room.

5. The purchaser shall provide the supplier's installation personnel with work meals as much as possible.

6. If necessary, a joint acceptance team consisting of the purchaser, supplier, and qualified testing units shall be formed to retest the shielding effectiveness of the shielding room, and the performance shall comply with the relevant indicators specified in the contract.

7. To ensure the fairness of the testing, if a third-party testing shielding room is required and the test results are qualified, the testing cost shall be borne by the purchaser; If the test results are not qualified, the testing costs shall be borne by the supplier and the supplier shall rectify them to be qualified. The repair and secondary testing costs incurred shall be borne by the supplier.

8. After the installation of the shielding room is completed, the purchaser shall dispatch a dedicated person to inspect the electrical, decorative, and other configuration equipment of the project in accordance with the relevant requirements of the contract formulated by both parties.

9. After the above project acceptance is qualified, the supplier shall deliver the project to the demander, and the acceptance work shall be completed.

10. The demand side of the shielding room is responsible for the project