Looking for 90s/2000s kids sci-fi show where creatures turn up in our world. Live action with bad CGI

Question

There is a show I watched when I was young, It aired on British TV somewhere around late 90s to 2000s. If I remember correctly, it starred a teen boy who fought creatures who came through to this world from another. I can't remember if the other world was a video game or not. I think he had a little sister as well.

I remember a scene took place in a fair where one of these creatures was loose and I halfway remember his sister was in danger at the fair because of the creature.

The show was live action but the creatures were this horrifyingly bad CGI.

As I said I recall very little, but the fair scene with the tiny rollercoaster you only see at fairs stuck with me. I also think there was something to do with electricity in there. It felt like a show was somewhere between Animorphs and Primeval.

Answer 1

Could it be 'Ace Lightning'?

From Wikipedia:

Ace Lightning is a children's television series co-produced by the BBC and Alliance Atlantis. The series was originally broadcast in the United Kingdom but was also aired in other countries including the United States, Australia, New Zealand and South Africa.1 The show was filmed in Canada, but the program was set in the United States. It ran for two seasons, and spawned a number of merchandising products. The series premiered on 4 September 2002 and ended on 18 May 2005

The programme featured live actors interacting with computer animated characters from a fictional video game. The series is significant in that until its creation, live action and CGI had not been attempted to such a huge and constant degree within a weekly television serial.

It was a pretty terrible show from what I remember and it definitely matches the criteria of 'bad cgi'. It also had a theme park/carnival setting as well as all the creatures and villians which matches your comment about scenes at a fairground.