为了研究±1 100 k V直流滤波器典型故障过电压的特点及其相应的保护措施,针对±1 100 k V昌吉-古泉直流输电工程,利用PSCAD计算并分析了双极全压运行方式、单极大地回线和单极金属回线运行方式下直流滤波器短路、滤波器高低压...为了研究±1 100 k V直流滤波器典型故障过电压的特点及其相应的保护措施,针对±1 100 k V昌吉-古泉直流输电工程,利用PSCAD计算并分析了双极全压运行方式、单极大地回线和单极金属回线运行方式下直流滤波器短路、滤波器高低压电容器组分别击穿等滤波器典型故障产生的过电压及其暂态特性,并在最具代表性的故障情况下,研究了避雷器对过电压特性的影响。基于此,进一步研究了保护控制策略对过电压与能量的影响。结果表明,整流侧发生直流滤波器短路故障时,过电压更为严重;单极金属回线下发生直流滤波器短路故障时,过电压更为严重且避雷器吸收能量过大;增设避雷器与保护控制后,关键节点的过电压值均低于该处的绝缘水平,避雷器吸收的能量也未超过其吸收能力。展开更多
Mancozeb is a multi-site fungicide used to control late blight （Phytophthora infestans） and early blight （Alternaria solani） in potatoes, and is currently due for re-approval as part of the EU Sustainable Use Dire...Mancozeb is a multi-site fungicide used to control late blight （Phytophthora infestans） and early blight （Alternaria solani） in potatoes, and is currently due for re-approval as part of the EU Sustainable Use Directive---Authorisation of Plant Protection Products Regulation （EC） No 1107/2009. In order to understand its value to the EU potato industry, a stakeholder survey was conducted to understand the implications for P. infestans control and the impact on EU potato production if mancozeb was not available. In total, 319 growers and advisers were surveyed in 8 countries： France, Germany, Ireland, Netherlands, Greece, Italy, Spain and the UK, to determine how they use mancozeb, potential alternative control strategies and the implications of withdrawal. This study demonstrates that mancozeb is a widely used and cost-effective multisite active ingredient, which is a highly valued means of control for P. infestans. Based on the survey results, a loss of mancozeb would lead to a reduction in gross margin for potato producers in these countries of 787 million to 507 million depending on the level of P. infestans pressure. The combined impact of high cost of production and increased risks is likely to lead to reductions in the availability of EU potatoes and increased costs to consumers. In addition, an assessment was completed to determine the impact of mancozeb withdrawal on fungicide resistance development to single-site acting fungicides, finding that the loss of a multi-site active ingredient like mancozeb would severely compromise fungicide resistance management.展开更多
文摘为了研究±1 100 k V直流滤波器典型故障过电压的特点及其相应的保护措施,针对±1 100 k V昌吉-古泉直流输电工程,利用PSCAD计算并分析了双极全压运行方式、单极大地回线和单极金属回线运行方式下直流滤波器短路、滤波器高低压电容器组分别击穿等滤波器典型故障产生的过电压及其暂态特性,并在最具代表性的故障情况下,研究了避雷器对过电压特性的影响。基于此,进一步研究了保护控制策略对过电压与能量的影响。结果表明,整流侧发生直流滤波器短路故障时,过电压更为严重;单极金属回线下发生直流滤波器短路故障时,过电压更为严重且避雷器吸收能量过大;增设避雷器与保护控制后,关键节点的过电压值均低于该处的绝缘水平,避雷器吸收的能量也未超过其吸收能力。
文摘Mancozeb is a multi-site fungicide used to control late blight （Phytophthora infestans） and early blight （Alternaria solani） in potatoes, and is currently due for re-approval as part of the EU Sustainable Use Directive---Authorisation of Plant Protection Products Regulation （EC） No 1107/2009. In order to understand its value to the EU potato industry, a stakeholder survey was conducted to understand the implications for P. infestans control and the impact on EU potato production if mancozeb was not available. In total, 319 growers and advisers were surveyed in 8 countries： France, Germany, Ireland, Netherlands, Greece, Italy, Spain and the UK, to determine how they use mancozeb, potential alternative control strategies and the implications of withdrawal. This study demonstrates that mancozeb is a widely used and cost-effective multisite active ingredient, which is a highly valued means of control for P. infestans. Based on the survey results, a loss of mancozeb would lead to a reduction in gross margin for potato producers in these countries of 787 million to 507 million depending on the level of P. infestans pressure. The combined impact of high cost of production and increased risks is likely to lead to reductions in the availability of EU potatoes and increased costs to consumers. In addition, an assessment was completed to determine the impact of mancozeb withdrawal on fungicide resistance development to single-site acting fungicides, finding that the loss of a multi-site active ingredient like mancozeb would severely compromise fungicide resistance management.
