```uclid
model leader_election_protocol
  type pid_t = int;
  type msg_t = int;

  const n : pid_t;

  record process_state_t {
    id : pid_t;
    channel : array [pid_t][msg_t];
    leader : boolean;
  }

  var processes : array [pid_t][process_state_t];

  init {
    for pid : pid_t :: processes[pid].id = pid;
    for pid : pid_t :: processes[pid].leader = false;
    for pid : pid_t :: processes[pid].channel[pid] = processes[pid].id;
  }

  define next_pid(pid: pid_t) : pid_t {
    return (pid % n) + 1;
  }

  procedure send_msg(src_pid : pid_t, msg : msg_t)
  {
    processes[next_pid(src_pid)].channel[src_pid] = msg;
  }

  procedure receive_msg(pid : pid_t) returns (msg : msg_t)
  {
    return processes[pid].channel[pid];
  }

  procedure process_action(pid : pid_t)
  {
    var m : msg_t;
    m = receive_msg(pid);
    if (m = processes[pid].id) {
      processes[pid].leader = true;
    } else if (m > processes[pid].id) {
      send_msg(pid, m);
    }
  }

  next {
    for pid : pid_t :: process_action(pid);
  }

  control {
    init;
    while (true) {
      next;
    }
  }
end
```

This UCLID5 code models the leader election protocol for `n` processes arranged in a ring topology. Each process sends their ID via unidirectional channel. The process executes repeatedly receiving messages and either stops if the message matches their ID (indicating they have been elected leader) or forwards the message if it is higher. The `next_pid` function ensures that messages are passed to the next process in the ring. The program simulates this scenario until a leader is elected.