dimensions for medium voltage cells 12 kV and 24 kV

Report

 

on the dimensions and sizes of medium voltage cells 12 kV and 24 kV

 1- The IEC standard did not specify any dimensions for medium voltage cells 12 kV and 24 kV, nor did it specify any distances between the faces inside the cell, nor did it stipulate the lengths of the leak path inside the cell.

The published specifications of the Egyptian Ministry of Electricity and Energy represented by the Electricity Holding Company, the Electricity Distribution Companies, and the Electricity Transmission Company are in agreement with the international standards IEC for medium voltage cells in not specifying any dimensions of the cell or any internal dimensions except for the text that the length of the leakage path min.

 Specific leakage path inside metal clad medium voltage cells must not be less than 2 cm/kV for either 12 kV or 24 kV as shown in Table No. (2) and Table No. (3) of Clause 4.2. 1 of the published specifications.

As you are aware, the IEC committee that sets international electrical standards has left the manufacturers the freedom to design medium pressure cells 12 kV and 24 kV and did not restrict them to any dimensions, but demanded that the cells they design and manufacture must pass qualitative tests ( Type tests) stipulated in the IEC so that they can be accepted for installation and operation in electrical networks in different countries.

It also demanded manufacturers that the manufactured cells must pass routine tests in the factory according to the values ​​indicated in the IEC international standards before handing them over to customers, installing and operating them in electrical networks.

Based on the foregoing, the international company "Siemens" has designed and manufactured a new generation of medium voltage cells, the Simoprime model, for voltages 12 kV and 24 kV, and conducted all the qualitative tests (Type tests) stipulated by the international standards (IEC). Before being put up for installation and operation in electrical networks in different countries.

The international company "Siemens" has taken into account that the dimensions of the cells are suitable for the tasks that are installed inside them from components such as the dynamic circuit breaker (CB), voltage and current transformers (CT&VT), earthing switch, etc. so that all of them conform to the international standard specifications IEC placed for each of them.

The international company "Siemens" also took into account that the dimensions of the cells achieve the lowest possible cost for civil works, which represents a significant value of the total cost of the project in which these cells are used.

According to what was mentioned above, the international company "Siemens" has settled on the following dimensions of Simoprime cells for voltage 12 kV and 24 kV

1. 12 KV, 25 KA/ 31.5 KA, 3 S ≤ 1250A

                Width = 600 mm.

                Height = 2253 mm. with standard LV Compartment.

                Depth = 1860 mm.

2. 12 KV, 25 KA/ 31.5 KA, 3 S, > 1250A – 2500A

                      Width = 800 mm.

                      Height = 2253 mm with standard LV Compartment.

                      Depth = 1860 mm.

3. 12 KV, 40 KA, 3 S, ≤ 1250 A – 3600 A

                      Width = 800 mm.

                      Height = 2253 with standard LV Compartment.

                      Depth = 1860 mm.

4. 24 KV, 25 KA, 3 S, ≤ 1250A

    Width = 800 mm.

    Height = 2250 mm with standard LV Compartment

    Depth = 1900 mm.

5. 24 KV, 25 KA, 3 S, > 1250A - 2500A

     Width = 1000 mm.

      Height = 2250 mm with standard LV Compartment.

      Depth = 1900 mm.

It is worth noting that the 12 kV and 24 kV medium voltage cells of the Simoprime model with the dimensions shown above have successfully passed all the qualitative tests stipulated by the international standard specifications IEC, and they also achieve the following standards: -

1- IEC 62271 - 200 A.C metal-enclosed switchgear and control gear

                                     for rated voltages above 1 KV and up to and

                                                    including 52 KV.

2- IEC 62271 – 1 Common clause for high–voltage switchgear and

                                                    control gear standards.

3- IEC 62271 – 100 High – voltage alternating current circuit –

                                                    breakers.

4- IEC 60071 – 1 Insulation coordination for equipment in three –

                                                    phase systems above 1 KV.

5- IEC 62271 – 105 High – voltage alternating current switch – fuse

                                                    combinations.

6- IEC 60529 Degree of protection provided by enclosures

                                                    (IP - Code).

7- IEC 62271 – 102 Alternating current disconnectors (isolators) and

                                                     earthing switches

8- IEC 60282 - 1 Current limiting fuses.

9- IEC 61243 - 5 Working under voltage - voltage detectors - part 5:

                                                     Voltage detection systems.

10- IEC 60044 – 1 Current transformer.

11- IEC 6044 – 2 Voltages transformers.

In addition to the above, the medium voltage cell has passed 12 kV, 31.5 kV, 3 s, 2500 amps Simoprime model, and the voltage cell