The business environment of distribution networks is changing rapidly. Electricity price rises and technology advances, particularly in distributed energy resources such as solar PV and battery storage, mean that cust...
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ISBN:
(纸本)9781509014064
The business environment of distribution networks is changing rapidly. Electricity price rises and technology advances, particularly in distributed energy resources such as solar PV and battery storage, mean that customers have new choices for their energy supply. Adoption of these new technologies, together with more efficient appliances, is leading to changing network utilisation which can contribute to rising electricity prices. Electricity tariffs that are not cost reflective, are also contributing to market distortions. This paper describes the results from an application of cost reflective tariffs with customers that have distributed energy resources within a single Ergon Energy low voltage network.
The work presented in this paper aims to assess the impact of electric vehicle (EV) on distribution networks. An study is performed showing how the network impact can dramatically change if applying smart charging str...
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ISBN:
(纸本)9781479960767
The work presented in this paper aims to assess the impact of electric vehicle (EV) on distribution networks. An study is performed showing how the network impact can dramatically change if applying smart charging strategies opportunely integrated with other distributed energy resources (DER) with respect to a less-smart baseline operation. This paper focuses on the resolution of network constraints -voltage level violations in the short term, i.e. maintaining reliability and quality of service at transmission and distribution system operator (TSO and DSO) levels. A Spanish case study is derived in this work to obtain realistic network conditions within a 24-hour time horizon and one network reconfiguration is applied causing voltage level violations near a low voltage (LV) network including EV microgrids. The DSO then activates the available flexibility capacity of such microgrids in order to remove such violations. This case study is implemented in an experimental laboratory test and results are discussed regarding the impact of this congestion management strategy on the network and also real power flow and communication aspects.
Increased penetration of distributed energy resources (DER) and large-scale deployment of renewable energy sources are challenging the entire architecture of traditional power system. Microgrid, featuring higher flexi...
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Increased penetration of distributed energy resources (DER) and large-scale deployment of renewable energy sources are challenging the entire architecture of traditional power system. Microgrid, featuring higher flexibility and reliability, becomes an attractive candidate for the configuration of future electrical power system. This paper gives an overview of DER units in the grid interactive ac microgrid. The options in structures and control methods of power electronics interfaced DER units are described. Instantaneous load sharing strategies among DER units in the islanded microgrid operations are discussed pointing out the importance of closed loop system output impedance for the power electronics interfaced DER units.
This paper presents a new on-line certificate validation method which provides higher degree of security, scalability, and interoperability than do the pre-existing approaches. It combines two basic data structures fo...
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This paper presents a new on-line certificate validation method which provides higher degree of security, scalability, and interoperability than do the pre-existing approaches. It combines two basic data structures for certificate revocation, certificate revocation list (CRL) and the authenticated dictionary such as certificate revocation tree (CRT), into a single framework by utilizing the component matching enabled lightweight directory access protocol (LDAP) service. With the new method, end entities that want to check the validity of certificates can request an extended LDAP search operation with a component matching assertion against all revoked certificate components in a CRL and check whether a revoked certificate having the asserted serial number is found. In order to ensure strong security without requiring trusted directories, CRLs are represented as an authenticated dictionary when decoded from distinguished encoding rules (DER) to an internal ASN.1 representation. The information required to construct the authenticated dictionary is conveyed from the certificate authority (CA) via a new CRL extension. The proposed method facilitates a number of advantages over the previous approaches like online certificate status protocol (OCSP): 1) it enables higher security because it does not require trusted entities other than the CA such as trusted LDAP servers and trusted OCSP responders; 2) it improves scalability and performance because it does not require responses to be signed as in OCSP; 3) it can intemperate well with the existing CRL framework; and 4) it does not need support for additional protocols for on-line certificate validation because it is built on LDAP which is the main access method to download CRLs. The proposed method can also be used as a CRL back-end of OCSP to offload CRL management and to enhance its trust model.
The evolutionary changes in the electricity system are reshaping the system operation and control to achieve a more sustainable environment. In this transition, distributed energy resources (DERs) may introduce some p...
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ISBN:
(纸本)9781479917631
The evolutionary changes in the electricity system are reshaping the system operation and control to achieve a more sustainable environment. In this transition, distributed energy resources (DERs) may introduce some problems, such as intermittent features, but could also play an important role on accommodating the intermittence and assisting system operation. A proper aggregation and coordination scheme of DER units is required to enable the flexibility provision in an economical and efficient manner. In the meanwhile, nondistruptive control of the units is essential to guarantee their long-term active participation. In addition, a newly established system should also allow and coordinate other controllable grid facilities. This paper proposes a hierarchical operating framework for DER units and controllable grid assets in a market environment. Voltage regulation as a common distributed system service is used for case study. The necessity of the coordination between DER units and the grid facilities, e.g., on-load tap-changer (OLTC), is addressed.
Climate change concerns, mandatory requirements for the renewable portfolio standards, incentives offered by the Government, and cost reduction in renewables and distributed energy sources (DER) are some of the drivin...
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Climate change concerns, mandatory requirements for the renewable portfolio standards, incentives offered by the Government, and cost reduction in renewables and distributed energy sources (DER) are some of the driving forces for the steep growth in DER installations. DERs are commonly connected near the load in the electric power distribution system. DER includes renewable energy such as wind and solar, fossil-fuel based generation-microturbines, and other distributed energy storage elements. In this research, a novel methodology is developed that optimizes the sizing and placement of DER on electrical distribution feeders based on technical and economic considerations. The paper also evaluates the methodology on the IEEE 34-bus system.
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