Week 8 - Natural Convection-II
Aim: To create a non conformal assembly of the given voltage panel and investigate the temperature rise for natural convection condition.
Introduction:
Electrical Control Panel:
Electrical control panel is a CRCA(cold rolled close annealed) ms sheet enclosure that contains electrical switchgear that controls and monitors a mechanical process electrically.
In process plant one or more motor control by a piece of equipment that called an electrical control panel. The electrical control panel starts or stops many equipment's through switchgear and SCADA automation by using MCCB, Contractor, PLC, Overload relay and plug-in relay, etc.
There are three types of electrical control panel
1.Power control center (PCC Panel)
2. Motor Control center (MCC Panel)
3. Automation Panel (SCADA PLC Panel)
PCC Panel:
Fig. 1 shows PCC Panel that contains all of the electrical switchgear like an air circuit breaker, MCC's, mcb, and suitable size aluminum or copper busbar. The main circuit breaker is where the power comes into the control panel for all of the switchgear. This circuit breaker generally has an isolate on the panel that allows us to shut off the power. The power that comes into the panel can be anywhere from 440 volts to 800V AC.
Fig. 1 PCC panel
MCC Panel
Fig. 2 shows an MCC panel. In many commercial and Industry applications, multiple electric motors are required, and it is often desirable to control some of the motors. The apparatus designed for this type of function is the Motor Control Center Panel (MCC Panel).
When a motor operation runs with the protection of overload relays or solid-state motor controllers. An MCC Panel manufacturer has a control from a remote or local that is called a motor control panel. There are combinations of different types of starters like direct online (DOL) Starter or star-delta starter.
MCC Panel (motor control center) is used for motor control of various electrical power Industries. Therefore, it is most important in electricity. MCC panel is an Electrical control panel in LT panels. In other words, it can control the motor from generation to production.
Fig. 2 MCC Panel
Automation panel (SCADA PLC Panel)
Fig. 3 shows SCADA and PLC panel. Automation panel (Scada PLC panel) is a Programmable digital computer also known as PLC Automation Panel is one of the most important and efficient kinds of control panels. Which are generally used in a variety of electronic and electrical circuit fittings. Integrated with solid PLC logic and flawless PLC hardware programming.
Fig. 3 SCADA and PLC Panel
Procedure:
Step 1: Create the cabinet for the given dimensions as shown in Fig 4.
Fig. 4 Cabinet
Similarly, create an enclosure with the following dimensions as shown in Fig. 5
Fig. 5 Enclosure
Step 2: Create the circuit breaker and the busbars as mentioned in the problem. The front view and the isomeric view is shown in Fig 6a and 6b respectively.
Fig. 6a. Front view of the Panel. 
Fig. 6b. Isometric view of the panel
Step 3. Creating assemblies.
Nested assemblies is created under assembly 1. Totally 7 assemblies are created. Slack settings are given for assembly 1.
Step 4: Mesh Generation
After generating the mesh, around 165936 elements were generated.
The X-plane, Y-plane and Z Plane meshing is shown in Fig. 7.
Fig. 7. Mesh in x-plane, y-plane and z-plane respectively.
The quality of the mesh is shown below
Step 5: Problem settings and solver settings
The problem is solved for velocity and temperature under natural convection condition without radiation chosing zero equation turbulence model.
The pressure is solved for standard discretization scheme. The momentum and energy equations were solved considering first order upwind scheme.
Step 6: Results and discussion
The velocity vectors is shown in fig 8.
Fig. 8 Velocity Vectors
The temperature contour is shown in Fig. 9
Fig. 9 Temperature Contour
The object face contour of circuit breakers and bub bars are shown below.
Conclusion:
The maximum temperature in the panel is found to be around 195oC in the main circuit breaker. A slightly bigger panel size is required for air to flow around the circuit breaker for more heat dissipation in order to keep the temperature of the circuit breakers with in the operating range.