IN the Spain of 1992, will there be too much going on? In addition to the big-ticket attractions of the 1992 Summer Olympic Games in Barcelona and the 1992 Universal Exposition in Seville, the country will be celebrating the "Quinto Centenario the 500th anniversary of Christopher Columbus's voyage of 1492 - and Madrid for one year will become the cultural capital of Europe.Organizers of the quincentenary and of Madrid's year as cultural capital say they will complement rather than rival the splashier events with activities that round out Spain's year in the spotlight. "Spain will celebrate a grand fiesta in 1992, but each of its elements will be very different, intending to provide a satisfying whole for the human spirit," says Pablo Lopez de Osaba, director general of Madrid European Capital of Culture 1992. "Expo is buildings and the Olympics is sports, but the quincentenary is an idea, a way of approaching things next year and in the future," says Isabel Horrillo, a program coordinator with the quincentenary's Andalucian delegation in Seville. "It is a way of getting closer to Latin America, and bringing it closer to Europe." The commemoration includes cultural events, economic, scientific, and other research projects, book publishing and restoration work in Spain and Latin America, all related to the peri od of Spanish discovery and colonization that began with Columbus's voyage. As for whether there will be too much going on for even the Madrilno to absorb, Mr. Lopez de Osaba says that Madrid, after 500 years as the crossroads of Christian, Jewish, and Islamic cultures, after serving as the seat of the Hapsburgs and the Bourbons, and after building a bridge from America to Europe, "is a city where people are accustomed to, and offer themselves the time to take part in, the spectacle of life. In that way," he says, "is Madrid an authentic capital of the world."