d by market reforms. They did, however, raise some issues that will need to be addressed in the future concerning investment in ensuring system security in competitive markets. Although investment in transmission capacity may help to improve transmission system security to a degree over a period of time, it is not expected to be a critical factor in managing the "operational" reliability of an existing transmission system (IEA, 2005c). This is because system security or reliability is not simply a function of available transmission line capacity. More importantly, there is a need for investment in upgrading and improving system operating tools that would enhance system operators' capacity to effectively monitor, understand and more flexibly control transmission systems in real time. Investment to strengthen the competence and expertise of system operators and other professionals directly involved in the task of maintaining system security helps to improve real-time responses, particularly during emergency situations. Investments that enhance the likelihood of system components operating as designed, especially during emergency situations, may also help to improve transmission system security. The costs of such investments are modest compared with the cost of building transmission capacity. Investment will increasingly need to be directed at improving the quality of supply, rather than simply meeting increased demand for reliable electricity service. This essentially involves ensuring a stable voltage. When the voltage dips below a stable threshold the system can become unstable; this leads to a collapse in voltage, with the potential to cause serious damage to motors and electronic equipment and appliances at the point of use. The growing prevalence of electronics as we move into the digital age is increasing the importance of high-precision electricity supply (EPRI, 2003). There is enormous potential for developing and deploying technologies to improve operating tools to enhance transmission and distribution sys