Realization of Distribution Network Feeder Terminal Unit based on Dual-DSP

This paper presents the design proposal of distribution network monitoring unit based on dual-DSP. A detailed description of the hardware structure about the device is introduced which including signal scheduling, SPI communication, the serial human-computer communication and network communication. Additionally, the paper describes the software process about the master and slave DSPs. Then the analog precision test and the protection response test are carried out. The result shows that the design proposal is correct.

Fault Location Method Based on Transient Frequency in Non-Effectively Grounded Distribution Network

In order to solve the fault location problem of single phase to-earth fault in non-effectively grounded distribution network, a new fault location method based on transient frequency of zero-mode current was presented. The difference of transient frequency of zero-mode current between detecting points before and after the fault point is analyzed. This method is realized by the distribution automation (DA) system and does not require additional equipment. The zero-mode current is detected and the frequency of its transient component is calculated by the feeder terminal unit (FTU). The fault section can be located by master station according to comparing the transient frequency at different detecting point on the fault feeder. Results of digital simulation demonstrated the accuracy and feasibility of this method.

Harmonization of Feeder Terminal Unit Information Model Based on IEC 61850 and IEC 61968/61970

The feeder terminal unit (FTU) is a kind of distribution remote terminal unit along distribution feeders and communication with master stations (MS) in control centre. IEC 61970/61968/61850 are three important standard for smart grid. IEC 61850 logical nodes are used for FTUs information model, and IEC 61970/61968 common information model (CIM) are using in MS. To realizing seamless access FTUs to MS, harmonization of IEC 61850 and IEC 61968/61970 are studied. The status information (such as position of switch) and measurement information (such as current, voltage) are realizing mapping from IEC 61850 to IEC 61968/61970. So, the seamless communication between the master station and FTU is realized.

A Distributed Protection and Control Scheme for Distribution Network with DG

High penetration level of distributed generation (DG) connected to distribution network makes the protection and control in the traditional distribution network face great difficulties, so this paper proposed a protection and control technology based on advanced feeder terminal unit (AFTU). According to DGs capability and load, the scheme divides the distribution network into several zones in advance, each of which can operate in island mode. Circuit breakers (CB) together with AFTU are installed at the beginning of feeder, the border of two zones and the point of DG connection. AFTUs interconnect with each other through the fiber optic network. AFTU detects the local electrical quantities in real-time and exchanges information with others through the fiber optic network. It can locate the faulted zone quickly to achieve fault isolation and island operation according to local and neighboring information. The reclosing of CB and the control of reconnection of DG are also designed. The case analysis illustrates the feasibility of the proposed distributed protection and control scheme.

Application of IEC61850-80-1 in Peer-to-Peer Communication between Feeder Terminal Units

The trend towards using IEC61850 standards in feeder terminal unit (FTU) design is inexorable, but at present in China, IEC60870-5-104 is mostly used in distribution automatic system (DAS) information exchange. Thus it can be seen that IEC61850 standard will coexist with IEC60870-5 standard for a long time. IEC61850-80-1 provides the method of exchanging information from IEC61850 CDC-based data model using IEC60870-5-101 or IEC60870-5-104. This paper makes a brief analysis on the structure of DAS based on IEC61850, proposes the information model of FTU in accordance to IEC61850 and maps the information model to IEC60870-5-104 using IEC61850-80-1, which takes the advantage of IEC60870-5-104’s excellent real-time performance to realize peer-to-peer communication between FTUs.