WHEN Lu Ping, China's chief of Hong Kong affairs, arrives tonight, it will be into a territory that members of his immediate family know intimately. Both his wife and son have worked for various Hong Kong companies for years, and have easy access to the territory's top businessmen and community leaders. Their combined knowledge of the territory may give some the impression that they are a conduit of information for Mr Lu, who has not visited the territory for the past two years because of the row over Chris Patten's political reforms. However, a close look at the relationship suggests this is unlikely to be the case. Mr Lu's wife, Xi Liang, has worked in Hong Kong since 1985, while his son, Kenneth Lu Gong, has been employed by a string of Hong Kong companies. As China's most senior official on Hong Kong affairs, Mr Lu makes it his business to know what is going on here - yet his absence from Hong Kong has made this difficult. Neither his wife nor son will be at Hung Hom station to greet him when his train arrives from Guangzhou. Some suggest the Lu family has grown apart. Others say their absence is purely a coincidence. According to colleagues, Ms Xi, deputy general manager of China International Trade and Investment Corporation (Hong Kong), is currently on the mainland on business, believed to be using her engineering background to oversee the construction of new power plants. Ms Xi, 65, works from a plush office in The Landmark, and is not expected back in Hong Kong until the middle of the month, according to her secretary. A frequent traveller to the mainland, she was also away during her husband's last Hong Kong visit, in early 1992. Like many other mainland couples of their generation, they work apart and rarely see each other, leaving little scope for Hong Kong businessmen to win favours from Mr Lu by pampering his wife. The younger Lu has worked for a number of Hong Kong companies. He is currently employed by Li Ka-shing's Cheung Kong. Previous employers include the Sino Land property group, headed by Robert Ng Chee-siong, and Shell Hong Kong. Mr Lu began working for Cheung Kong at the beginning of the year. And although he is based in Beijing, his value to Hong Kong companies comes through his connections with other influential sons of senior Chinese leaders - the so-called ''princelings''. Besides frequent job changes, the younger Mr Lu has had a troubled personal life in recent years. His first wife divorced him after she was sent to work in Paris. He remarried last year. Those seeking favours from his father's office through the younger Mr Lu have little chance of success. ''The old man would never allow it,'' said a friend of Mr Lu for 40 years. ''He's very strict about not using personal connections to win favours and gets very angry when anything like that comes up.'' With so many Hong Kong people wanting to see the elder Mr Lu, from the Governor down, the absence of his family will probably be overlooked. Mr Lu is not the kind of person to let family matters mar the important visit. The trip, originally expected to last only until Friday, will now continue until April 9. Despite the extension, which will give him more time to meet people, he will not visit the Governor. A visit by any Chinese official to Mr Patten, once dubbed by Mr Lu as a ''man of guilt for 1,000 years'', with the reforms row still unresolved would be seen in Beijing as completely impolitic. It would also run into opposition from local Xinhua (New China News Agency) chief Zhou Nan. Forgetting the people Mr Lu will not see in Hong Kong, he is still in for a busy time - and it will not all be pleasant. From the moment his train from Guangzhou pulls in at 7 pm, Mr Lu and his entourage of 23 aides and mainland Preliminary Working Committee members will be the target of protests. Operation Save Xi Yang, an umbrella organisation campaigning for the release of the jailed Ming Pao journalist, is organising a major demonstration to mark Mr Lu's arrival. A small radical group, Kick Out The PWC, is also planning a protest. Two car-loads of Special Branch and Xinhua bodyguards will whisk Mr Lu - and secretary Liu Zhenxin - past the protesters as he leaves Hung Hom for Mr Zhou's villa in Stanley Beach Road, his base during the visit. Friends say Mr Lu dislikes the Stanley villa, regarding it as too far out of town, although that will not deter demonstrators who intend to camp outside while he is in residence. Its choice for this visit has already sparked speculation of a tacit agreement with Mr Zhou that the Hong Kong and Macau Affairs Office director will stay out of the spotlight this time around. Also accompanying Mr Lu will be top Hong Kong affairs officials Wang Fengchao, Xu Ze, and Zhang Liangdong. Mr Lu's first meeting, a gathering of the Preliminary Working Committee political sub-group, will be held tomorrow in the Bank of China Building. This will be followed by a 6 pm ceremony on the 17th floor to mark the issuing of the Bank of China's first Hong Kong dollar banknotes, at which Mr Lu will rub shoulders with minor government officials, such as Monetary Authority Chief Executive Joseph Yam Chi-kwong. While these two events have been widely presented as the reason for Mr Lu's trip, in reality they are little more than a politically convenient excuse. During the past year, Mr Lu had made it clear to friends that ordinarily he could not return to the territory until the political reform row was resolved. THE idea of holding PWC sub-group meetings in Hong Kong is nothing new. Local members, tired of flying to Beijing almost every month, have long recommended it as a chance for mainland officials to enjoy closer consultation with the local community. But the decision to make this week's sub-group meeting the first to be held in the territory appears to be politically motivated. Although the last session discussed the sensitive subject of the civil service, controversially concluding that all 180,000 public employees should be asked if they wished to remain after the handover, it was nonetheless held in Beijing. ''This [the plan to hold the latest meeting in Hong Kong] will boost the importance of the Preliminary Working Committee,'' said Professor Lau Siu-kai, an academic and political sub-group member. ''The symbolic meaning of Mr Lu's visit is more important than the subject of the meeting.'' He said the visit showed Beijing had given up all hope of co-operating with Britain, and would now concentrate on winning support in the local community, a point repeatedly stressed by Chinese leaders in recent months. Professor Lau also claimed a meeting with the Governor would send out the wrong signals. ''Pictures of Mr Lu shaking hands with Mr Patten would be misleading to Hong Kong people,'' he said. ''This . . . might be used by Mr Patten to 'prove' his strategy is correct; that China's angry reaction to his [political] reform proposals is only temporary.'' The political sub-group meeting, which ends on Tuesday, will be followed by a session of its economic counterpart. It is not yet clear if Mr Lu will attend the meeting, scheduled for Wednesday and Thursday. He has skipped several in the past. However, he will lunch with members on Thursday. Much of his remaining time is expected to be spent pursuing the united front strategy in meetings with local leftists. Many have already been invited to a cocktail reception at the China Resources Building in Wan Chai on Tuesday. Some Hong Kong Affairs advisers have also requested a separate session with him, and a dinner - with, as yet, unknown guests - has been arranged for Thursday at the Hilton hotel. The Heung Yee Kuk, which is seeking support in its battle with the Government over New Territories land rights, is also likely to see him. As on previous visits, Mr Lu will visit the Kowloon headquarters of the 170,000-strong Federation of Trade Unions, China's main grassroots supporter in Hong Kong. This is scheduled for next Sunday. But Mr Lu's expected emphasis on meetings with Beijing's hard-core supporters, rather than more representative members of the community, has already sparked criticism from one local leftist. Maverick National People's Congress (NPC) delegate Liu Yiu-chu called on the pro-Beijing camp to step back and allow Mr Lu time to meet ordinary Hong Kong people. ''This time the NPC delegates, Chinese People's Political Consultation Conference delegates and Hong Kong Affairs advisers should not fight for meetings with Mr Lu because we already have many opportunities and channels to convey our opinions to him,'' she said. ''This opportunity should be left to other Hong Kong people.'' Ms Liu said the territory's delegates and advisers numbered only a few hundred and could hardly claim to represent Hong Kong's population of six million.