Xiao Juan Han

Analysis on Thermal Economy and Peak-Shaving Capability for Combined Heat and Power (CHP) Unit in Varying Operating Conditions

Based on the principle of featured through-current area being constant, calculation model for parameters of regenerative steam extraction of CHP unit in different heating conditions is developed in this paper through using FROTRAN software. The generated output and thermal economy of the CHP unit are calculated by using the method of equivalent enthalpy drop, and the accuracy of the model is verified. With the purpose to analyze the rationality of different calculation methods, the distribution ratio of coal consumption for heat supply and coal consumption rate for power generation are calculated through method of equivalent enthalpy drop, heat quantity method and method of actual enthalpy drop under the same operating condition. Moreover, according to the operation test on the unit, the highest and lowest generated output of the CHP under various loads of heat supply are determined, which will provide a basis to the subsequent thermoelectric units in participating in peak shaving of power grid.

Analysis Software of Power Quality and Power Regulation for Wind Farm Based on DEWETRON

t is a powerful guarantee for the safe and stable operation of the grid to detect and study its characteristics such as the active power, the reactive power, the flicker and the harmonic. Dewetron5000 system and its software can be used to collect and analyze the experimental data of power system without getting the corresponding conclusion quickly, directly and clearly. In view of the above questions, the software has been developed to test the power quality for wind farm into the grid, the collected data after being processed by the secondary can display the situations of power quality and power regulation clearly and fast. The software has a very important role on the development of the test standard and system for wind power grid.

Advanced Control of Boiler Drum Water Level Based on Cloud Model Theories

In order to implement an excellent control for boiler drum water level at a power plant, nonlinear systems with long time-delay, a new intelligent control algorithm based on cloud model theories is proposed. According to the requirements of boiler drum water level control system, a two-dimensional cloud model controller is designed by incorporating deviation signals and deviation changing rates of the drum water level as its inputs, three parameters of PID as its outputs which are adjusted real-time by generating cloud mapping rules to realize fast and accurate control for the drum water level. Computer simulation shows that the cloud model controller proposed in this paper can significantly reduce the overshoot and response time of drum water level.

The Design of High-Voltage Cable Partial Discharge On-Line Monitoring System Software

This article is one of the series of papers about the Cross-linked polyethylene cable partial discharge on-line monitoring and positioning system. Design and application, which is about the Cross-linked polyethylene cable partial discharge on-line monitoring and positioning system software, is discussed from the run analysis , log record and PC control, etc. Basing on the field running effect of the Cross-linked polyethylene cable partial discharge on-line monitoring and positioning system, it manifests the correctness and effectiveness of the above methods.

Research on the Capacity of In-Depth Peak Regulation of Large-Scale Heat Supply Unit Based on Characteristics of Thermal Storage of Heat Supply Network and Buildings

Against the backdrop that wind power is always abandoned in heat supply period in winter after wind power is taken into power grid in northern areas of China and there exists a big proportion of large-scale heat supply units in power grid, a method for in-depth peak regulation of large-scale heat supply unit based on characteristics of thermal storage of heat supply network and buildings is put forward in this paper, and a mathematical model for in-depth peak regulation is established. The calculation in a case indicates that the change of heat production of large-scale heat supply unit will not affect the quality of heat supply to a certain extent. During heat supply period, thermal load of heat supply network shall be moderately lowered to coordinate with the in-depth peak regulation when power grid is at its low ebb, and heat supply shall be moderately decreased based on characteristics of thermal storage of heat supply network and buildings when the peak regulation capacity of power grid is very limited, which indicates that it is feasible and practical to help power grid go through its low ebb with the peak regulation capacity gained here. Through the mathematical model established in this paper, time of thermal storage and thermal release as well as such units capacity of in-depth peak regulation can be calculated, which provides a scientific basis for dispatcher of power grid to conduct in-depth peak regulation of heat supply unit.

Functions and Theoretical Basis of Partial Discharge On-Line Monitoring System for High-Voltage Cables

A partial discharge (PD) on-line monitoring and positioning system for high-voltage cables based on double-ended testing technology is developed. The hardware of this system includes a high-frequency current sensor, site PD signal acquisition and PD monitoring server. In order to achieve real-time monitoring and remote diagnostics of the XLPE cable partial discharge status, the designed software system is divided into front-end control system and remote diagnostic system. And finally, the correctness and effectiveness of the system is verified by XLPE cable partial discharge testing.

Research and Development on the On-Line Monitoring System of Cable Line Arrester

The research and development on the on-line monitoring system of cable line arrester is discussed from system composition, main functions of system, main features of the system and system development tools, and the practical experience of the construction indicates the necessity and effectiveness of the method.

Leading Phase Operation and Voltage Regulation of Synchronous Generators

The leading phase operation of generator is an effective method to reduce voltage of the key point which is much high in valley load period. This paper reviews the history on leading phase of generator and introduces the current situation on stable monitoring of the generators leading phase capacity. Meanwhile, this paper proposes main restricted conditions of generator leading phase and analyzed in details. At last some experiments are performed for part generating sets with a capacity of 100MW above in one province and obtained the experiment results on voltage regulation through leading phase of synchronous generating sets.

The Influence on Reactive Voltage of Large Scale Wind Power Connected to Grid

Large scale wind power integration has influenced the safety of power system. Taking wind power integration in Jilin as example, the paper describes the influencing factors of large scale wind power integration on reactive power of the grid in detail firstly, then analyze the reactive voltage in four typical ways, and discuss the impact of the wind power fluctuations on the grid reactive voltage.

Detection Method and Control Strategy of Active Power for Wind Farm Connected into Grid

As one of main clean energies, wind power has been developed fast, but the fluctuations of active power at a wind farm is a huge challenge for the grid system, thus it is essential for wind farm connected into grid to detection the active power. This paper studied control strategies and detection methods of the active power at a wind farm. Simulation results showed the effective detection of active power at a wind farm can improve the characteristics of the grid and the ability of wind farm to regulate the grid and increase the scheduled ability of wind farm.