The scope of work is to collect input data from the site and then perform Short circuit studies, Relay coordination and Arc Flash studies for a pharmaceutical Laboratory plant.
The Plant receives the power supply via 33kV Transmission line from APSPDCL. The electrical system is fed from 33 kV grid through 1 No of 33/0.433kV 2000kVA transformer and 1 No of 33/0.433kV 2500kVA transformer. When the APSPDCL supply is not available i.e.: Emergency condition, two numbers of 1010kVA 0.415kV DG is used to feed the system.
The Network comprises 33 kV panels, two numbers of PCC panels and thirty numbers of 0.415 kV MCC distribution panels. The plant has 34 buses which consist of LV panels with both fuses & LV MCCBs with thermal magnetic and electronic releases.
As the plant is typically two decades old, the MCCB’s condition are in critical state and the accuracy of the settings was uncertain. We need to ensure that all 34 switchgears & MCCs are coordinated well with each other and the fault-clearing time settings are limiting the Incident Energy Levels at a minimum.
Also, plant has some distribution panels with a fuse as a protective device to isolate the circuit in case of faults. So, the main challenge in this project was to analyse protective device coordination with the fuses and old MCCB’s. Hence, we recommended to re-examine the existing relay settings to the customer.
The Key challenge is that few MCCs the incident energy is extremely high due to delayed fault clearing when Diesel Generator is running. Retaining the coordination in Grid mode and DG mode along with ensuring the minimum possible incident energy is explored wherever possible.
🔸Arc Flash studies were performed at each bus in accordance with IEEE 1584 – 2018, IEEE 1584.1 – 2022, and appropriate Personal Protective Equipment (PPE) was recommended in accordance with NFPA-70E 2021 guidelines.
🔸ETAP 22 software was used to run the simulation produce results.
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