Fixed a bug in REGF1

[zaidmahmood]

A bug was fixed in REGF1 model.

[sonarcloud[bot]]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.0% Duplication

[cuihantao]

Thanks a lot!!

[codecov[bot]]

Codecov Report

Base: 78.40% // Head: 78.40% // No change to project coverage :thumbsup:

Coverage data is based on head (023957e) compared to base (da1d0cc). Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #390 +/- ## ======================================== Coverage 78.40% 78.40% ======================================== Files 179 179 Lines 14687 14687 ======================================== Hits 11516 11516 Misses 3171 3171 ``` | [Impacted Files](https://codecov.io/gh/cuihantao/andes/pull/390?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Hantao+Cui) | Coverage Δ | | |---|---|---| | [andes/models/renewable/regf1.py](https://codecov.io/gh/cuihantao/andes/pull/390/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Hantao+Cui#diff-YW5kZXMvbW9kZWxzL3JlbmV3YWJsZS9yZWdmMS5weQ==) | `99.01% <100.00%> (ø)` | | | [andes/models/line/jumper.py](https://codecov.io/gh/cuihantao/andes/pull/390/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Hantao+Cui#diff-YW5kZXMvbW9kZWxzL2xpbmUvanVtcGVyLnB5) | `100.00% <0.00%> (ø)` | | Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Hantao+Cui). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Hantao+Cui)

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