The credit score formulas are proprietary secrets, but the inputs to the formulas are known. Credit scores are based solely on the information in your credit report.
Therefore, to answer your question, all you need to do is look at your credit reports. If you do not see the corporate card reporting on your credit report, then things like credit limits and utilization from that account are not currently affecting your credit score, positively or negatively. If your corporate credit card is reported on your credit report, then realize that late payments and utilization on these cards might affect your credit score. (Note that even if the corporate card is not reporting now, they may begin reporting at some point in the future.)
In my limited experience (in the U.S.), I've had one corporate credit card in the past from a previous employer. Although they told me that I was jointly responsible for the card with the company, the card was never reported on my credit report. For that I am grateful: there was at least one time when the company was late with a payment.
The other thing that can (temporarily) affect your credit score is a "hard pull" credit inquiry. When you got the corporate card, did a credit inquiry appear on your report? If so, then it is possible that they might pull your report again before increasing the limit. However, I doubt they would do this. Your employer has a very high corporate-wide limit with the bank. Individual limits on the cards are not very important, and the bank would typically just increase an individual card limit on request from the company.